Data4UrbanMobility was presented on the 20th November 2018 during the Leibniz Startup & Industry Event Artificial Intelligence. The PROJEKTIONISTEN® GmbH together with the Research Center L3S explained current project outcomes like the D4UM-App and the Dashboard to interested visitors.

We very much enjoyed the interesting discussion and are very happy about all participants in our Citizen Science App “MiC – Move in the City”.

• Haushaltsnahe Dienstleistungen (noch?) überwiegend schwarz. Technical Report (24), Anger, Christina; Enste, Dominik (2022).

  Nur etwa jeder zehnte Haushalt nutzt bisher die Unterstützung durch eine Haushaltshilfe, darunter nur wenige Haushalte mit Kindern im Haushalt. Der Bedarf ist jedoch insbesondere für Familien in den letzten zwei Jahren durch den zeitweiligen Ausfall von Kindergärten und Schulen und dem damit erhöhten Betreuungsaufwand für Kinder gestiegen. Durch finanzielle Unterstützung in Form von Gutscheinen plant die Bundesregierung nun, hier Abhilfe zu schaffen und gleich mehrere Ziele zu erreichen.
• Predicting fluorescence quantum yields for molecules in solution: A critical assessment of the harmonic approximation and the choice of the lineshape function. Humeniuk, Alexander; Bužančić, Margarita; Hoche, Joscha; Cerezo, Javier; Mitrić, Roland; Santoro, Fabrizio; Bonačić-Koutecký, Vlasta (2020). 152(5)
• Comparison of moving and fixed basis sets for nonadiabatic quantum dynamics at conical intersections. Titov, Evgenii; Humeniuk, Alexander; Mitrić, Roland (2020). 528 110526.
• Tetraiododiborane(4) (B2I4) is a Polymer Based on sp3 Boron in the Solid State. Muessig, Jonas H.; Lisinetskaya, Polina; Dewhurst, Rian D.; Bertermann, Rüdiger; Thaler, Melanie; Mitrić, Roland; Braunschweig, Holger (2020). 59(14) 5531–5535.
• Correlating Nanoscale Optical Coherence Length and Microscale Topography in Organic Materials by Coherent Two-Dimensional Microspectroscopy. Li, Donghai; Titov, Evgenii; Roedel, Maximilian; Kolb, Verena; Goetz, Sebastian; Mitric, Roland; Pflaum, Jens; Brixner, Tobias (2020). 20(9) 6452–6458.
• Do Xylylenes Isomerize in Pyrolysis?. Hirsch, Florian; Pachner, Kai; Fischer, Ingo; Issler, Kevin; Petersen, Jens; Mitric, Roland; Bakels, Sjors; Rijs, Anouk M. (2020). 21(14) 1515–1518.
• Impact of substituents on molecular properties and catalytic activities of trinuclear Ru macrocycles in water oxidation. Meza-Chincha, Ana-Lucia; Lindner, Joachim O.; Schindler, Dorothee; Schmidt, David; Krause, Ana-Maria; Röhr, Merle I. S.; Mitrić, Roland; Würthner, Frank (2020). 11(29) 7654–7664.

  Herein we report a broad series of new trinuclear supramolecular Ru(bda) macrocycles bearing different substituents at the axial or equatorial ligands which enabled investigation of substituent effects on the catalytic activities in chemical and photocatalytic water oxidation. Our detailed investigations revealed that the activities of these functionalized macrocycles in water oxidation are significantly affected by the position at which the substituents were introduced. Interestingly, this effect could not be explained based on the redox properties of the catalysts since these are not markedly influenced by the functionalization of the ligands. Instead, detailed investigations by X-ray crystal structure analysis and theoretical simulations showed that conformational changes imparted by the substituents are responsible for the variation of catalytic activities of the Ru macrocycles. For the first time, macrocyclic structure of this class of water oxidation catalysts is unequivocally confirmed and experimental indication for a hydrogen-bonded water network present in the cavity of the macrocycles is provided by crystal structure analysis. We ascribe the high catalytic efficiency of our Ru(bda) macrocycles to cooperative proton abstractions facilitated by such a network of preorganized water molecules in their cavity, which is reminiscent of catalytic activities of enzymes at active sites.
• Excitation energy transport in DNA modelled by multi-chromophoric field-induced surface hopping. Wohlgemuth, Matthias; Mitrić, Roland (2020). 22(29) 16536–16551.

  Absorption of ultraviolet light is known as a major source of carcinogenic mutations of DNA. The underlying processes of excitation energy dissipation are yet not fully understood. In this work we provide a new and generally applicable route for studying the excitation energy transport in multi-chromophoric complexes at an atomistic level. The surface-hopping approach in the frame of the extended Frenkel exciton model combined with QM/MM techniques allowed us to simulate the photodynamics of the alternating (dAdT)10:(dAdT)10 double-stranded DNA. In accordance with recent experiments, we find that the excited state decay is multiexponential, involving a long and a short component which are due to two distinct mechanisms: formation of long-lived delocalized excitonic and charge transfer states vs. ultrafast decaying localized states resembling those of the bare nucleobases. Our simulations explain all stages of the ultrafast photodynamics including initial photoexcitation, dynamical evolution out of the Franck–Condon region, excimer formation and nonradiative relaxation to the ground state.
• metaFALCON: A Program Package for Automatic Sampling of Conical Intersection Seams Using Multistate Metadynamics. Lindner, Joachim O.; Sultangaleeva, Karina; Röhr, Merle I. S.; Mitrić, Roland (2019). 15(6) 3450–3460.
• Experimental and theoretical 2p core-level spectra of size-selected gas-phase aluminum and silicon cluster cations: chemical shifts, geometric structure, and coordination-dependent screening. Walter, Michael; Vogel, Marlene; Zamudio-Bayer, Vicente; Lindblad, Rebecka; Reichenbach, Thomas; Hirsch, Konstantin; Langenberg, Andreas; Rittmann, Jochen; Kulesza, Alexander; Mitrić, Roland; Moseler, Michael; Möller, Thomas; von Issendorff, Bernd; Lau, J. Tobias (2019). 21(12) 6651–6661.

  We present 2p core-level spectra of size-selected aluminum and silicon cluster cations from soft X-ray photoionization efficiency curves and density functional theory. The experimental and theoretical results are in very good quantitative agreement and allow for geometric structure determination. New ground state geometries for Al12+, Si15+, Si16+, and Si19+ are proposed on this basis. The chemical shifts of the 2p electron binding energies reveal a substantial difference for aluminum and silicon clusters: while in aluminum the 2p electron binding energy decreases with increasing coordination number, no such correlation was observed for silicon. The 2p binding energy shifts in clusters of both elements differ strongly from those of the corresponding bulk matter. For aluminum clusters, the core-level shifts between outer shell atoms and the encapsulated atom are of opposite sign and one order of magnitude larger than the corresponding core-level shift between surface and bulk atoms in the solid. For silicon clusters, the core-level shifts are of the same order of magnitude in clusters and in bulk silicon but no obvious correlation of chemical shift and bond length, as present for reconstructed silicon surfaces, are observed.
• Dynamic exciton localisation in a pyrene–BODIPY–pyrene dye conjugate. Auerhammer, Nina; Schulz, Alexander; Schmiedel, Alexander; Holzapfel, Marco; Hoche, Joscha; Röhr, Merle I. S.; Mitric, Roland; Lambert, Christoph (2019). 21(18) 9013–9025.

  The photophysics of a molecular triad consisting of a BODIPY dye and two pyrene chromophores attached in 2-position are investigated by steady state and fs-time resolved transient absorption spectroscopy as well as by field induced surface hopping (FISH) simulations. While the steady state measurements indicate moderate chromophore interactions within the triad, the time resolved measurements show upon pyrene excitation a delocalised excited state which localises onto the BODIPY chromophore with a time constant of 0.12 ps. This could either be interpreted as an internal conversion process within the excitonically coupled chromophores or as an energy transfer from the pyrenes to the BODIPY dye. The analysis of FISH-trajectories reveals an oscillatory behaviour where the excitation hops between the pyrene units and the BODIPY dye several times until finally they become localised on the BODIPY chromophore within 100 fs. This is accompanied by an ultrafast nonradiative relaxation within the excitonic manifold mediated by the nonadiabatic coupling. Averaging over an ensemble of trajectories allowed us to simulate the electronic state population dynamics and determine the time constants for the nonradiative transitions that mediate the ultrafast energy transfer and exciton localisation on BODIPY.
• Probing ultrafast dynamics during and after passing through conical intersections. Adachi, Shunsuke; Schatteburg, Tom; Humeniuk, Alexander; Mitrić, Roland; Suzuki, Toshinori (2019). 21(26) 13902–13905.

  Time-resolved photoelectron spectroscopy using vacuum-UV probe pulses enables observing ultrafast dynamics during and after passing through conical intersections (CIs). The ring-puckering CI plays a prominent role following the ππ* photoexcitation of furan. More than 90% of the excited molecules safely return to the original ground state, while the remaining 10% transforms into isomers after passing through the puckering CI.
• Collective Response in DNA-Stabilized Silver Cluster Assemblies from First-Principles Simulations. Lisinetskaya, Polina G.; Mitrić, Roland (2019). 10(24) 7884–7889.
• Exploring the Excited-State Dynamics of Hydrocarbon Radicals, Biradicals, and Carbenes Using Time-Resolved Photoelectron Spectroscopy and Field-Induced Surface Hopping Simulations. Röder, Anja; Petersen, Jens; Issler, Kevin; Fischer, Ingo; Mitrić, Roland; Poisson, Lionel (2019). 123(50) 10643–10662.
• The origin of the solvent dependence of fluorescence quantum yields in dipolar merocyanine dyes. Hoche, Joscha; Schulz, Alexander; Dietrich, Lysanne Monika; Humeniuk, Alexander; Stolte, Matthias; Schmidt, David; Brixner, Tobias; Würthner, Frank; Mitric, Roland (2019). 10(48) 11013–11022.

  Fluorophores with high quantum yields are desired for a variety of applications. Optimization of promising chromophores requires an understanding of the non-radiative decay channels that compete with the emission of photons. We synthesized a new derivative of the famous laser dye 4-dicyanomethylen-2-methyl-6-p-dimethylaminostyryl-4H-pyran (DCM), i.e., merocyanine 4-(dicyanomethylene)-2-tert-butyl-6-[3-(3-butyl-benzothiazol-2-ylidene)1-propenyl]-4H-pyran (DCBT). We measured fluorescence lifetimes and quantum yields in a variety of solvents and found a trend opposite to the energy gap law. This motivated a theoretical investigation into the possible non-radiative decay channels. We propose that a barrier to a conical intersection exists that is very sensitive to the solvent polarity. The conical intersection is characterized by a twisted geometry which allows a subsequent photoisomerization. Transient absorption measurements confirmed the formation of a photoisomer in unpolar solvents, while the measurements of fluorescence quantum yields at low temperature demonstrated the existence of an activation energy barrier.
• Excited state dynamics and time-resolved photoelectron spectroscopy of para-xylylene. Issler, Kevin; Röder, Anja; Hirsch, Florian; Poisson, Lionel; Fischer, Ingo; Mitrić, Roland; Petersen, Jens (2018). 212 83–100.

  We investigated the excited-state dynamics of para-xylylene using a combination of field-induced surface hopping (FISH) simulations and time-resolved ionisation experiments. Our simulations predict an ultrafast decay of the initially excited bright state (S2/S3) to the S1 state on a sub-100 fs time scale, followed by return to the ground state within ∼1 ps. This is accompanied by a transient change of the biradical character of the molecule, as monitored by calculating natural orbital occupation numbers. Specifically, the initially low biradicality is increased by electronic excitation as well as by vibrational activation. Experimentally, para-xylylene was generated by pyrolysis from [2,2]paracyclophane and excited with 266 nm radiation into the S2/S3 bright state. The subsequent dynamics were followed using ionisation as the probe step, with both mass spectra and photoelectron spectra recorded as a function of pump–probe delay. The observed decay of photoelectron and photoion intensities closely matches the theoretical predictions and is consistent with the sequential mechanism found in the simulations. This mechanism exhibits characteristic signatures in both time-resolved mass and photoelectron spectra, in particular in the appearance of fragment ions that are exclusively generated from the S1 state. This allows for a separation of the S2 and S1 dynamics in the photoelectron and mass spectra. An excellent agreement between the observed and the simulated ion signal is observed.
• Diborene: Generation and Photoelectron Spectroscopy of an Inorganic Biradical. Schleier, Domenik; Humeniuk, Alexander; Reusch, Engelbert; Holzmeier, Fabian; Nunez-Reyes, Dianailys; Alcaraz, Christian; Garcia, Gustavo A.; Loison, Jean-Christophe; Fischer, Ingo; Mitric, Roland (2018). 9(20) 5921–5925.
• Davydov-type excitonic effects on the absorption spectra of parallel-stacked and herringbone aggregates of pentacene: Time-dependent density-functional theory and time-dependent density-functional tight binding. Darghouth, Ala Aldin M. H. M.; Correa, Gabriela Calinao; Juillard, Sacha; Casida, Mark E.; Humeniuk, Alexander; Mitrić, Roland (2018). 149(13)
• A block Jacobi method for complex skew-symmetric matrices with applications in the time-dependent variational principle. Humeniuk, Alexander; Mitrić, Roland (2018). 231 187–197.
• Disentangling the photochemistry of benzocyclobutenedione. Ma, Xiaonan; Wenzel, Michael; Schmitt, Hans-Christian; Flock, Marco; Reusch, Engelbert; Mitrić, Roland; Fischer, Ingo; Brixner, Tobias (2018). 20(22) 15434–15444.

  The ultrafast photophysics and photochemistry of benzocyclobutenedione (BCBD) dissolved in dichloromethane is investigated by transient absorption spectroscopy in both the IR and the UV/Vis regime. The molecule is excited at 300 nm to the S3 (ππ*) state and a time scale from roughly 100 fs to several nanoseconds is covered. The initially excited S3 deactivates quickly to the lower-lying S1 (nπ*) state. Three parallel photochemical reaction pathways starting in the S1 state that compete with deactivation to S0 are identified in the transient IR spectra, two of them consisting of a sequence of steps. DFT/TDDFT calculations of the normal modes of the reactant and various photoproducts support the analysis of the transient spectra. The rapid internal conversion (IC) to the S1 state of BCBD is followed by a sub-picosecond vibrational relaxation (VR) to S1 (ν = 0). In parallel BCBD loses one carbonyl group and forms benzocyclopropenone, which subsequently rearranges to cyclopentadienylidene ketene. Ring opening in the S1 (ν = 0) state produces vibrationally hot bisketene, which cools within 22 ps. This reaction competes with the intramolecular rearrangement to singlet oxacarbene, which subsequently converts into the triplet carbene via intersystem crossing (ISC). The late-time product identified in the transient UV/Vis spectra is probably due to dimerization of the carbene. Molecular dynamics (MD) simulations of the early-time photochemistry of BCBD successfully reproduce the formation of the three main photoproducts.
• Multistate metadynamics for automatic exploration of conical intersections. Lindner, Joachim O.; Röhr, Merle I. S.; Mitrić, Roland (2018). 97(5)
• Exciton Dynamics from Strong to Weak Coupling Limit Illustrated on a Series of Squaraine Dimers. Röhr, Merle I. S.; Marciniak, Henning; Hoche, Joscha; Schreck, Maximilian H.; Ceymann, Harald; Mitric, Roland; Lambert, Christoph (2018). 122(15) 8082–8093.
• Isolation of diborenes and their 90textdegree-twisted diradical congeners. Böhnke, Julian; Dellermann, Theresa; Celik, Mehmet Ali; Krummenacher, Ivo; Dewhurst, Rian D.; Demeshko, Serhiy; Ewing, William C.; Hammond, Kai; Heß, Merlin; Bill, Eckhard; Welz, Eileen; Röhr, Merle I. S.; Mitri’c, Roland; Engels, Bernd; Meyer, Franc; Braunschweig, Holger (2018). 9(1) 1197.

  Molecules containing multiple bonds between atoms---most often in the form of olefins---are ubiquitous in nature, commerce, and science, and as such have a huge impact on everyday life. Given their prominence, over the last few decades, frequent attempts have been made to perturb the structure and reactivity of multiply-bound species through bending and twisting. However, only modest success has been achieved in the quest to completely twist double bonds in order to homolytically cleave the associated \($\pi$\) bond. Here, we present the isolation of double-bond-containing species based on boron, as well as their fully twisted diradical congeners, by the incorporation of attached groups with different electronic properties. The compounds comprise a structurally authenticated set of diamagnetic multiply-bound and diradical singly-bound congeners of the same class of compound.
• Exciton localization in excited-state dynamics of a tetracene trimer: a surface hopping LC-TDDFTB study. Titov, Evgenii; Humeniuk, Alexander; Mitrić, Roland (2018). 20(40) 25995–26007.

  Excitons in the molecular aggregates of chromophores are key participants in important processes such as photosynthesis or the functioning of organic photovoltaic devices. Therefore, the exploration of exciton dynamics is crucial. Here we report on exciton localization during excited-state dynamics of the recently synthesized tetracene trimer [Liu et al., Org. Lett., 2017, 19, 580]. We employ the surface hopping approach to nonadiabatic molecular dynamics in conjunction with the long-range corrected time-dependent density functional tight binding (LC-TDDFTB) method [Humeniuk and Mitrić, Comput. Phys. Commun., 2017, 221, 174]. Utilizing a set of descriptors based on the transition density matrix, we perform comprehensive analysis of exciton dynamics. The obtained results reveal an ultrafast exciton localization to a single tetracene unit of the trimer during excited-state dynamics, along with exciton transfer between units.
• Deciphering environment effects in peptide bond solvation dynamics by experiment and theory. Wohlgemuth, Matthias; Miyazaki, Mitsuhiko; Tsukada, Kohei; Weiler, Martin; Dopfer, Otto; Fujii, Masaaki; Mitrić, Roland (2017). 19(33) 22564–22572.

  Most proteins work in aqueous solution and the interaction with water strongly affects their structure and function. However, experimentally the motion of a specific single water molecule is difficult to trace by conventional methods, because they average over the heterogeneous solvation structure of bulk water surrounding the protein. Here, we provide a detailed atomistic picture of the water rearrangement dynamics around the –CONH– peptide linkage in the two model systems formanilide and acetanilide, which simply differ by the presence of a methyl group at the peptide linkage. The combination of picosecond pump–probe time-resolved infrared spectroscopy and molecular dynamics simulations demonstrates that the solvation dynamics at the molecular level is strongly influenced by this small structural difference. The effective timescales for solvent migration triggered by ionization are mainly controlled by the efficiency of the kinetic energy redistribution rather than the shape of the potential energy surface. This approach provides a fundamental understanding of protein hydration and may help to design functional molecules in solution with tailored properties.
• Femtosecond dynamics of the 2-methylallyl radical: A computational and experimental study. Röder, Anja; Issler, Kevin; Poisson, Lionel; Humeniuk, Alexander; Wohlgemuth, Matthias; Comte, Michel; Lepetit, Fabien; Fischer, Ingo; Mitric, Roland; Petersen, Jens (2017). 147(1)
• Supramolecular Approaches to Improve the Performance of Ruthenium‐Based Water Oxidation Catalysts. Kunz, Valentin; Schmidt, David; Röhr, Merle I. S.; Mitrić, Roland; Würthner, Frank (2017). 7(16)
• Ultrafast Photodynamics of Glucose. Petersen, Jens; Lindner, Joachim O.; Mitrić, Roland (2017). 122(1) 19–27.
• The mechanism of excimer formation: an experimental and theoretical study on the pyrene dimer. Hoche, Joscha; Schmitt, Hans-Christian; Humeniuk, Alexander; Fischer, Ingo; Mitrić, Roland; Röhr, Merle I. S. (2017). 19(36) 25002–25015.

  The understanding of excimer formation in organic materials is of fundamental importance, since excimers profoundly influence their functional performance in applications such as light-harvesting, photovoltaics or organic electronics. We present a joint experimental and theoretical study of the ultrafast dynamics of excimer formation in the pyrene dimer in a supersonic jet, which is the archetype of an excimer forming system. We perform simulations of the nonadiabatic photodynamics in the frame of TDDFT that reveal two distinct excimer formation pathways in the gas-phase dimer. The first pathway involves local excited state relaxation close to the initial Franck–Condon geometry that is characterized by a strong excitation of the stacking coordinate exhibiting damped oscillations with a period of 350 fs that persist for several picoseconds. The second excimer forming pathway involves large amplitude oscillations along the parallel shift coordinate with a period of ≈900 fs that after intramolecular vibrational energy redistribution leads to the formation of a perfectly stacked dimer. The electronic relaxation within the excitonic manifold is mediated by the presence of intermolecular conical intersections formed between fully delocalized excitonic states. Such conical intersections may generally arise in stacked π-conjugated aggregates due to the interplay between the long-range and short-range electronic coupling. The simulations are supported by picosecond photoionization experiments in a supersonic jet that provide a time-constant for the excimer formation of around 6–7 ps, in good agreement with theory. Finally, in order to explore how the crystal environment influences the excimer formation dynamics we perform large scale QM/MM nonadiabatic dynamics simulations on a pyrene crystal in the framework of the long-range corrected tight-binding TDDFT. In contrast to the isolated dimer, the excimer formation in the crystal follows a single reaction pathway in which the initially excited parallel slip motion is strongly damped by the interaction with the surrounding molecules leading to the slow excimer stabilization on a picosecond time scale.
• DFTBaby: A software package for non-adiabatic molecular dynamics simulations based on long-range corrected tight-binding TD-DFT(B). Humeniuk, Alexander; Mitrić, Roland (2017). 221 174–202.
• Cooperative water oxidation catalysis in a series of trinuclear metallosupramolecular ruthenium macrocycles. Kunz, Valentin; Lindner, Joachim O.; Schulze, Marcus; Röhr, Merle I. S.; Schmidt, David; Mitrić, Roland; Würthner, Frank (2017). 10(10) 2137–2153.

  A series of trinuclear metallosupramolecular Ru(bda) macrocycles has been synthesized and the impact of the ring size on the catalytic activity in homogeneous water oxidation has been elucidated (bda = 2,2′-bipyridine-6,6′-dicarboxylate). Kinetic experiments revealed that for all macrocyclic catalysts a proton-coupled oxidation event is rate-determining. Distinct H/D kinetic isotope effects (KIE) have been observed for the individual macrocycles, which follow the same tendency like the catalytic activity where an intermediate ring size exhibits the best performance. To get insight into the different molecular properties, molecular dynamics simulations using a QM/MM approach have been performed for all reaction steps, revealing that the size of the cavity strongly influences the hydrogen-bonded water network inside the macrocyclic structure and thus, important proton-coupled reaction steps of the catalytic cycle. For the most active catalysts, all reactive sites point into the interior of the cavity, which is supported by a single crystal X-ray analysis of the largest macrocycle, and a cooperative effect between the individual Ru(bda) centers facilitating proton abstraction has been substantiated. On the other hand, different structural conformations predominate the smaller macrocycles, which prevent efficient interactions between the Ru(bda) centers.
• First-principles simulation of light propagation and exciton dynamics in metal cluster nanostructures. Lisinetskaya, Polina G.; Röhr, Merle I. S.; Mitri’c, Roland (2016). 122(6) 175.

  We present a theoretical approach for the simulation of the electric field and exciton propagation in ordered arrays constructed of molecular-sized noble metal clusters bound to organic polymer templates. In order to describe the electronic coupling between individual constituents of the nanostructure we use the ab initio parameterized transition charge method which is more accurate than the usual dipole--dipole coupling. The electronic population dynamics in the nanostructure under an external laser pulse excitation is simulated by numerical integration of the time-dependent Schrödinger equation employing the fully coupled Hamiltonian. The solution of the TDSE gives rise to time-dependent partial point charges for each subunit of the nanostructure, and the spatio-temporal electric field distribution is evaluated by means of classical electrodynamics methods. The time-dependent partial charges are determined based on the stationary partial and transition charges obtained in the framework of the TDDFT. In order to treat large plasmonic nanostructures constructed of many constituents, the approximate self-consistent iterative approach presented in (Lisinetskaya and Mitri\'c in Phys Rev B 89:035433, 2014) is modified to include the transition-charge-based interaction. The developed methods are used to study the optical response and exciton dynamics of \\($\$\)\backslashhbox\Ag\\_\3\^\+\\\($\$\)and porphyrin-Ag4 dimers. Subsequently, the spatio-temporal electric field distribution in a ring constructed of ten porphyrin-Ag4 subunits under the action of circularly polarized laser pulse is simulated. The presented methodology provides a theoretical basis for the investigation of coupled light-exciton propagation in nanoarchitectures built from molecular size metal nanoclusters in which quantum confinement effects are important.
• Vibrationally resolved optical spectra and ultrafast electronic relaxation dynamics of diamantane. Röhr, Merle I. S.; Mitrić, Roland; Petersen, Jens (2016). 18(12) 8701–8709.

  We present theoretical simulations of the vibrationally resolved photoabsorption and photoemission spectra of diamantane combined with nonadiabatic dynamics simulations in order to identify the state responsible for the measured photoluminescence of diamantane and to determine the mechanism and the time-scales of the electronic state relaxation. Diamantane is a prototype representative of the diamondoid class of hydrocarbons which have recently gained significant interest due to their unique electronic properties. This molecule is characterised by an almost dark first excited state, which therefore cannot be directly excited. Moreover, the calculated vertical transition from the geometrically relaxed first excited state to the ground state also bears no intensity. However, recent experiments suggest that the observed photoluminescence originates from the lowest excited state. We have performed spectral simulations in the frame of the Herzberg–Teller approximation for vibronic transitions, which goes beyond the Franck–Condon approximation of constant transition dipole moments and takes into account their linear dependence on the geometrical deformations. In this way, the available experimental spectrum could be fully reproduced, resolving the issue about the origin of the photoluminescence. Moreover, the photoemission from the first excited state also implies that ultrafast nonradiative processes have to take place after the initial excitation of the bright electronic states. We have determined the mechanism and time-scales of these relaxation processes by performing nonadiabatic dynamics simulations in the manifold of s- and p-type Rydberg excited states. The simulations demonstrate that the lowest excited electronic state of diamantane gains significant population from higher-lying states already after several hundreds of femtoseconds. Thus, our dynamics simulations combined with spectra calculated using the Herzberg–Teller approximation allow us to fully explain the observed photoabsorption and photoemission properties of diamantane.
• Dynamics of Isolated 1,8-Naphthalimide and N-Methyl-1,8-naphthalimide: An Experimental and Computational Study. Gerbich, Thiemo; Schmitt, Hans-Christian; Fischer, Ingo; Mitrić, Roland; Petersen, Jens (2016). 120(13) 2089–2095.
• Excited state nonadiabatic dynamics of bare and hydrated anionic gold clusters Au3−[H2O]n (n = 0–2). Lisinetskaya, Polina G.; Braun, Christian; Proch, Sebastian; Kim, Young Dok; Ganteför, Gerd; Mitrić, Roland (2016). 18(9) 6411–6419.

  We present a joint theoretical and experimental study of excited state dynamics in pure and hydrated anionic gold clusters Au3−[H2O]n (n = 0–2). We employ mixed quantum-classical dynamics combined with femtosecond time-resolved photoelectron spectroscopy in order to investigate the influence of hydration on excited state lifetimes and photo-dissociation dynamics. A gradual decrease of the excited state lifetime with the number of adsorbed water molecules as well as gold cluster fragmentation quenching by two or more water molecules are observed both in experiment and in simulations. Non-radiative relaxation and dissociation in excited states are found to be responsible for the excited state population depletion. Time constants of these two processes strongly depend on the number of water molecules leading to the possibility to modulate excited state dynamics and fragmentation of the anionic cluster by adsorption of water molecules.
• Non-adiabatic dynamics around a conical intersection with surface-hopping coupled coherent states. Humeniuk, Alexander; Mitrić, Roland (2016). 144(23)
• Excitonic Properties of Ordered Metal Nanocluster Arrays: 2D Silver Clusters at Multiporphyrin Templates. Röhr, Merle I. S.; Lisinetskaya, Polina G.; Mitric, Roland (2016). 120(26) 4465–4472.
• Photochemical Chiral Symmetry Breaking in Alanine. Wohlgemuth, Matthias; Mitrić, Roland (2016). 120(45) 8976–8982.
• Long-range correction for tight-binding TD-DFT. Humeniuk, Alexander; Mitrić, Roland (2015). 143(13)
• Energy Transfer Between Squaraine Polymer Sections: From Helix to Zigzag and All the Way Back. Lambert, Christoph; Koch, Federico; Völker, Sebastian F.; Schmiedel, Alexander; Holzapfel, Marco; Humeniuk, Alexander; Röhr, Merle I. S.; Mitric, Roland; Brixner, Tobias (2015). 137(24) 7851–7861.
• Time-Resolved Study of 1,8-Naphthalic Anhydride and 1,4,5,8-Naphthalene-tetracarboxylic Dianhydride. Gerbich, Thiemo; Schmitt, Hans-Christian; Fischer, Ingo; Petersen, Jens; Albert, Julian; Mitrić, Roland (2015). 119(23) 6006–6016.
• Optimal control of light propagation and exciton transfer in arrays of molecular-like noble-metal clusters. Lisinetskaya, Polina G.; Mitrić, Roland (2015). 91(12)
• Site-dependence of van der Waals interaction explains exciton spectra of double-walled tubular J-aggregates. Megow, Jörg; Röhr, Merle I. S.; Schmidt am Busch, Marcel; Renger, Thomas; Mitrić, Roland; Kirstein, Stefan; Rabe, Jürgen P.; May, Volkhard (2015). 17(10) 6741–6747.

  The simulation of the optical properties of supramolecular aggregates requires the development of methods, which are able to treat a large number of coupled chromophores interacting with the environment. Since it is currently not possible to treat large systems by quantum chemistry, the Frenkel exciton model is a valuable alternative. In this work we show how the Frenkel exciton model can be extended in order to explain the excitonic spectra of a specific double-walled tubular dye aggregate explicitly taking into account dispersive energy shifts of ground and excited states due to van der Waals interaction with all surrounding molecules. The experimentally observed splitting is well explained by the site-dependent energy shift of molecules placed at the inner or outer side of the double-walled tube, respectively. Therefore we can conclude that inclusion of the site-dependent dispersive effect in the theoretical description of optical properties of nanoscaled dye aggregates is mandatory.
• Single water solvation dynamics in the 4-aminobenzonitrile–water cluster cation revealed by picosecond time-resolved infrared spectroscopy. Miyazaki, Mitsuhiko; Nakamura, Takashi; Wohlgemuth, Matthias; Mitrić, Roland; Dopfer, Otto; Fujii, Masaaki (2015). 17(44) 29969–29977.

  The dynamics of a solvent is important for many chemical and biological processes. Here, the migration dynamics of a single water molecule is triggered by the photoionization of the 4-aminobenzonitrile–water (4ABN–W) cluster and monitored in real time by picosecond time-resolved IR (ps TRIR) spectroscopy. In the neutral cluster, water is hydrogen-bonded to the CN group. When this CN-bound cluster is selectively ionized with an excess energy of 1238 cm−1, water migrates with a lifetime of τ = 17 ps from the CN to the NH2 group, forming a more stable 4ABN+–W(NH) isomer with a yield of unity. By decreasing the ionization excess energy, the yield of the CN → NH2 reaction is reduced. The relatively slow migration in comparison to the ionization-induced solvent dynamics in the related acetanilide–water cluster cation (τ = 5 ps) is discussed in terms of the internal excess energy after photoionization and the shape of the potential energy surface.
• Laser-induced fluorescence of free diamondoid molecules. Richter, Robert; Röhr, Merle I. S.; Zimmermann, Tobias; Petersen, Jens; Heidrich, Christoph; Rahner, Ramon; Möller, Thomas; Dahl, Jeremy E.; Carlson, Robert M. K.; Mitric, Roland; Rander, Torbjörn; Merli, Andrea (2015). 17(6) 4739–4749.

  We observe the fluorescence of pristine diamondoids in the gas phase, excited using narrow band ultraviolet laser light. The emission spectra show well-defined features, which can be attributed to transitions from the excited electronic state into different vibrational modes of the electronic ground state. We assign the normal modes responsible for the vibrational bands, and determine the geometry of the excited states. Calculations indicate that for large diamondoids, the spectral bands do not result from progressions of single modes, but rather from combination bands composed of a large number of Δv = 1 transitions. The vibrational modes determining the spectral envelope can mainly be assigned to wagging and twisting modes of the surface atoms. We conclude that our theoretical approach accurately describes the photophysics in diamondoids and possibly other hydrocarbons in general.
• Time- and Angle-Resolved Photoemission Spectroscopy of Hydrated Electrons Near a Liquid Water Surface. Yamamoto, Yo-ichi; Suzuki, Yoshi-Ichi; Tomasello, Gaia; Horio, Takuya; Karashima, Shutaro; Mitríc, Roland; Suzuki, Toshinori (2014). 112(18)
• Solvation Dynamics of a Single Water Molecule Probed by Infrared Spectra—Theory Meets Experiment. Wohlgemuth, Matthias; Miyazaki, Mitsuhiko; Weiler, Martin; Sakai, Makoto; Dopfer, Otto; Fujii, Masaaki; Mitrić, Roland (2014). 53(52) 14601–14604.
• Excited states from quantum Monte Carlo in the basis of Slater determinants. Humeniuk, Alexander; Mitrić, Roland (2014). 141(19)
• Exploring Ultrafast Dynamics of Pyrazine by Time-Resolved Photoelectron Imaging. Tomasello, Gaia; Humeniuk, Alexander; Mitrić, Roland (2014). 118(37) 8437–8445.
• Ab initiosimulations of light propagation in silver cluster nanostructures. Lisinetskaya, Polina G.; Mitrić, Roland (2014). 89(3)
• The nature of electronic excitations at the metal–bioorganic interface illustrated on histidine–silver hybrids. Sanader, Željka; Mitrić, Roland; Bonačić-Koutecký, Vlasta; Bellina, Bruno; Antoine, Rodolphe; Dugourd, Philippe (2014). 16(3) 1257–1261.

  We present a joint theoretical and experimental study of the structure selective optical properties of cationic and anionic histidine–silver complexes with Ag and Ag3 which were prepared in the gas phase using mass spectroscopy coupled to electrospray ion source. Our TDDFT calculations provide general insight into the nature of electronic excitations at the metal–bioorganic interface that involve π–π* excitation within bioorganic subunits, charge transfer between two subunits and intrametallic excitations. The binding of silver to histidine, one of the most important amino acids, induces red shift in the optical absorption of protonated histidine particularly for anionic species. The presence of the smallest metallic subunit Ag3 increases the intensity of low energy transitions of histidine illustrating a metal cluster-induced enhancement of absorption of biomolecules in hybrid systems. Comparison of calculated absorption spectra with experimental photofragmentation yield provides structural assignment of the measured spectroscopic patterns. Our findings may serve to establish silver-labeling as the tool for the detection of histidine or histidine-tagged proteins.
• Size and shape dependent photoluminescence and excited state decay rates of diamondoids. Richter, Robert; Wolter, David; Zimmermann, Tobias; Landt, Lasse; Knecht, Andre; Heidrich, Christoph; Merli, Andrea; Dopfer, Otto; Reiß, Philipp; Ehresmann, Arno; Petersen, Jens; Dahl, Jeremy E.; Carlson, Robert M. K.; Bostedt, Christoph; Möller, Thomas; Mitric, Roland; Rander, Torbjörn (2014). 16(7) 3070–3076.

  We present photoluminescence spectra and excited state decay rates of a series of diamondoids, which represent molecular structural analogues to hydrogen-passivated bulk diamond. Specific isomers of the five smallest diamondoids (adamantane–pentamantane) have been brought into the gas phase and irradiated with synchrotron radiation. All investigated compounds show intrinsic photoluminescence in the ultraviolet spectral region. The emission spectra exhibit pronounced vibrational fine structure which is analyzed using quantum chemical calculations. We show that the geometrical relaxation of the first excited state of adamantane, exhibiting Rydberg character, leads to the loss of Td symmetry. The luminescence of adamantane is attributed to a transition from the delocalized first excited state into different vibrational modes of the electronic ground state. Similar geometrical changes of the excited state structure have also been identified in the other investigated diamondoids. The excited state decay rates show a clear dependence on the size of the diamondoid, but are independent of the particle geometry, further indicating a loss of particle symmetry upon electronic excitation.
• Photodissociation dynamics of propargylene, HCCCH. Giegerich, Jens; Petersen, Jens; Mitrić, Roland; Fischer, Ingo (2014). 16(13) 6294–6302.

  We report a joint theoretical and experimental study on the photodissociation of the C3H2 isomer propargylene, HCCCH, combining velocity map imaging with nonadiabatic trajectory surface hopping calculations. Propargylene loses an H-atom, after laser excitation at around 250 nm, presumably to the T6 state. The photofragment angular distribution exhibits only a very small anisotropy, but the H-atom translational energy distribution extends to high energies and shows an expectation value of 〈fT〉, the fraction of excess energy released as translation, of 48%, outside the range expected for a statistical reaction mechanism. The computations suggest a predissociation in the T4–T6 state and lead to a translational energy distribution and photofragment angular distribution that match the experimentally observed ones very well.
• Time-resolved photoelectron imaging spectra from non-adiabatic molecular dynamics simulations. Humeniuk, Alexander; Wohlgemuth, Matthias; Suzuki, Toshinori; Mitrić, Roland (2013). 139(13)
• Tuning Structural and Optical Properties of Thiolate-Protected Silver Clusters by Formation of a Silver Core with Confined Electrons. Gell, Lars; Kulesza, Alexander; Petersen, Jens; Röhr, Merle I. S.; Mitrić, Roland; Bonačić-Koutecký, Vlasta (2013). 117(28) 14824–14831.
• Nonlinear Absorption Dynamics Using Field‐Induced Surface Hopping: Zinc Porphyrin in Water. Röhr, Merle I. S.; Petersen, Jens; Wohlgemuth, Matthias; Bonačić‐Koutecký, Vlasta; Mitrić, Roland (2013). 14(7) 1377–1386.
• Cation induced electrochromism in 2,4-dinitrophenylhydrazine (DNPH): Tuning optical properties of aromatic rings. Sanader, Željka; Brunet, Claire; Broyer, Michel; Antoine, Rodolphe; Dugourd, Philippe; Mitrić, Roland; Bonačić-Koutecký, Vlasta (2013). 570 22–25.
• Trendbericht Theoretische Chemie 2012. Mitric, Roland (2013). 61(3) 320–329.
• Formation and characterization of thioglycolic acid–silver cluster complexes. Bellina, Bruno; Antoine, Rodolphe; Broyer, Michel; Gell, Lars; Sanader, Željka; Mitrić, Roland; Bonačić-Koutecký, Vlasta; Dugourd, Philippe (2013). 42(23) 8328–8333.

  Gas phase reactivity observed in an ion trap was used to produce silver clusters protected with thioglycolic acid. Fragmentation pathways as well as optical properties were explored experimentally and theoretically. Sequential losses of SCH2 and CO2 in the ion trap lead to redox reactions with charge transfers between the metal part and the carboxylate and thiolate groups. This allows us to control the number of electrons in the metallic subunit and thus optical properties of the complexes. The presented formation process can be used as a prototype for tuning optical and chemical properties of ligated metal clusters by varying the number of confined electrons within the metallic subunit.
• Synthesis, characterization and optical properties of low nuclearity liganded silver clusters: Ag31(SG)19 and Ag15(SG)11. Bertorelle, Franck; Hamouda, Ramzi; Rayane, Driss; Broyer, Michel; Antoine, Rodolphe; Dugourd, Philippe; Gell, Lars; Kulesza, Alexander; Mitrić, Roland; Bonačić-Koutecký, Vlasta (2013). 5(12) 5637–5643.

  We report a simple synthesis of silver:glutathione (Ag:SG) clusters using a cyclic reduction under oxidative conditions. Two syntheses are described which lead to solutions containing well-defined Ag31(SG)19 and Ag15(SG)11 clusters that have been characterized by mass spectrometry. The optical properties of silver:glutathione (Ag:SG) cluster solutions have been investigated experimentally. In particular, the solution containing Ag15(SG)11 clusters shows a bright and photostable emission. For Ag31(SG)19 and Ag15(SG)11 clusters, the comparison of experimental findings with DFT and TDDFT calculations allowed us to reveal the structural and electronic properties of such low nuclearity liganded silver clusters.
• Speciation of Copper–Peptide Complexes in Water Solution Using DFTB and DFT Approaches: Case of the [Cu(HGGG)(Py)] Complex. Bruschi, Maurizio; Bertini, Luca; Bonačić-Koutecký, Vlasta; De Gioia, Luca; Mitrić, Roland; Zampella, Giuseppe; Fantucci, Piercarlo (2012). 116(22) 6250–6260.
• Binding motifs of silver in prion octarepeat model peptides: a joint ion mobility, IR and UV spectroscopies, and theoretical approach. Bellina, Bruno; Compagnon, Isabelle; MacAleese, Luke; Chirot, Fabien; Lemoine, Jérôme; Maître, Philippe; Broyer, Michel; Antoine, Rodolphe; Kulesza, Alexander; Mitrić, Roland; Bonačić-Koutecký, Vlasta; Dugourd, Philippe (2012). 14(32) 11433–11440.

  Transition metal-ion complexation is essential to the function and structural stability of many proteins. We studied silver complexation with the octarepeat motif ProHisGlyGlyGlyTrpGlyGln of the prion protein, which shows competitive sites for metal chelation including amide, indole and imidazole groups. This octapeptide is known as a favourable transition metal binding site in prion protein. We used ion mobility spectrometry (IMS), infrared multiple photon dissociation (IRMPD) spectroscopy and density functional theory calculations (DFT) to identify the binding motifs of a silver cation on HisGlyGlyGlyTrp peptide as well as on peptide subsequences. Ultra-violet photodissociation (UVPD) and collision induced dissociation mass spectrometry together with the time-dependent density functional method was then exploited to study the influence of binding sites on optical properties and on the ground and excited states reactivity of the peptide. We show that the metal cation is bound to the π-system of the indole group and a nitrogen atom of the imidazole group and that charge transfers from the indole group to the silver cation occur in excited electronic states.
• Laser pulse trains for controlling excited state dynamics of adenine in water. Petersen, Jens; Wohlgemuth, Matthias; Sellner, Bernhard; Bonačić-Koutecký, Vlasta; Lischka, Hans; Mitrić, Roland (2012). 14(14) 4687–4694.

  We investigate theoretically the control of the ultrafast excited state dynamics of adenine in water by laser pulse trains, with the aim to extend the excited state lifetime and to suppress nonradiative relaxation processes. For this purpose, we introduce the combination of our field-induced surface hopping method (FISH) with the quantum mechanical–molecular mechanical (QM/MM) technique for simulating the laser-driven dynamics in the condensed phase under explicit inclusion of the solvent environment. Moreover, we employ parametric pulse shaping in the frequency domain in order to design simplified laser pulse trains allowing to establish a direct link between the pulse parameters and the controlled dynamics. We construct pulse trains which achieve a high excitation efficiency and at the same time keep a high excited state population for a significantly extended time period compared to the uncontrolled dynamics. The control mechanism involves a sequential cycling of the population between the lowest and higher excited states, thereby utilizing the properties of the corresponding potential energy surfaces to avoid conical intersections and thus to suppress the nonradiative decay to the ground state. Our findings provide a means to increase the fluorescence yield of molecules with an intrinsically very short excited state lifetime, which can lead to novel applications of shaped laser fields in the context of biosensing.
• Electronic coherence within the semiclassical field-induced surface hopping method: strong field quantum control in K2. Petersen, Jens; Mitrić, Roland (2012). 14(23) 8299–8306.

  We demonstrate that the semiclassical field-induced surface hopping (FISH) method (Mitrić et al., Phys. Rev. A: At., Mol., Opt. Phys., 2009, 79, 053416.) accurately describes the selective coherent control of electronic state populations. With the example of the strong field control in the potassium dimer using phase-coherent double pulse sequences, we present a detailed comparison between FISH simulations and exact quantum dynamics. We show that for short pulses the variation of the time delay between the subpulses allows for a selective population of the desired final state with high efficiency. Furthermore, also for pulses of longer time duration, when substantial nuclear motion takes place during the action of the pulse, optimized pulse shapes can be obtained which lead to selective population transfer. For both types of pulses, the FISH method almost perfectly reproduces the exact quantum mechanical electronic population dynamics, fully taking account of the electronic coherence, and describes the leading features of the nuclear dynamics accurately. Due to the significantly higher computational efficiency of FISH as a trajectory-based method compared to full quantum dynamics simulations, this offers the possibility to theoretically investigate control experiments on realistic systems including all nuclear degrees of freedom.
• Theoretical study of structural and optical properties of noble metal cluster–dipeptide hybrids at defect centers of MgO. Kulesza, Alexander; Mitrić, Roland; Bonačić-Koutecký, Vlasta (2012). 14(26) 9330–9335.

  We present the theoretical investigation of structural and optical properties of silver and gold cluster–dipeptide hybrids bound to the FS defect of the MgO (100) surface. We use DFT and its TDDFT variant combined with the polarizable embedded cluster model for the description of the extended MgO environment. As model peptide we have chosen CysTrp since the cysteine residue interacts strongly with metal particles through the sulfur atom and tryptophan is the most important chromophoric amino acid. Our results show that in the case of CysTrp bound to the supported Ag4 cluster an intense optical signal arises at 400 nm. In contrast, in the case of gold no strongly localized absorption is present since the optical response of supported gold–peptide hybrids is dominated by a large number of low intensity d-electron excitations spread over a broad energy range. Such a localized optical signal which is present in supported silver hybrids can be exploited for the optical detection of peptides and thus can serve as basis for the development of biosensing materials.
• Silver cluster–biomolecule hybrids: from basics towards sensors. Bonačić-Koutecký, Vlasta; Kulesza, Alexander; Gell, Lars; Mitrić, Roland; Antoine, Rodolphe; Bertorelle, Franck; Hamouda, Ramzi; Rayane, Driss; Broyer, Michel; Tabarin, Thibault; Dugourd, Philippe (2012). 14(26) 9282–9290.

  We focus on the functional role of small silver clusters in model hybrid systems involving peptides in the context of a new generation of nanostructured materials for biosensing. The optical properties of hybrids in the gas phase and at support will be addressed with the aim to bridge fundamental and application aspects. We show that extension and enhancement of absorption of peptides can be achieved by small silver clusters due to the interaction of intense intracluster excitations with the π–π* excitations of chromophoric aminoacids. Moreover, we demonstrate that the binding of a peptide to a supported silver cluster can be detected by the optical fingerprint. This illustrates that supported silver clusters can serve as building blocks for biosensing materials. Moreover, the clusters can be used simultaneously to immobilize biomolecules and to increase the sensitivity of detection, thus replacing the standard use of organic dyes and providing label-free detection. Complementary to that, we show that protected silver clusters containing a cluster core and a shell liganded by thiolates exhibit absorption properties with intense transitions in the visible regime which are also suitable for biosensing applications.
• BLUF Hydrogen network dynamics and UV/Vis spectra: A combined molecular dynamics and quantum chemical study. Götze, Jan P.; Greco, Claudio; Mitrić, Roland; Bonačić‐Koutecký, Vlasta; Saalfrank, Peter (2012). 33(28) 2233–2242.
• Switching from molecular to bulklike dynamics in electronic relaxation of a small gold cluster. Stanzel, Jörg; Neeb, Matthias; Eberhardt, Wolfgang; Lisinetskaya, Polina G.; Petersen, Jens; Mitrić, Roland (2012). 85(1)
• Transient absorption spectra of excitation energy transfer in supramolecular complexes: A mixed quantum-classical description of pheophorbide-a systems. Megow, Jörg; Zelinskyy, Yaroslav; Röder, Beate; Kulesza, Alexander; Mitrić, Roland; May, Volkhard (2012). 522 103–107.
• Binary Neutral Metal Oxide Clusters with Oxygen Radical Centers for Catalytic Oxidation Reactions: From Cluster Models Toward Surfaces. Nößler, Melanie; Mitrić, Roland; Bonačić-Koutecký, Vlasta (2012). 116(21) 11570–11574.
• Photodynamics of Free and Solvated Tyrosine. Tomasello, Gaia; Wohlgemuth, Matthias; Petersen, Jens; Mitrić, Roland (2012). 116(30) 8762–8770.
• Exploring similarities in reactivity of superatom species: a combined theoretical and experimental investigation. Tyo, Eric C.; Nöβler Melanie; Rabe, Sabine; Harmon, Christopher L.; Mitrić, Roland; Bonačić-Koutecký, Vlasta; Castleman, A. W. (2012). 14(6) 1846–1849.

  The replacement of group 10-based materials by superatoms has gained great attention due to studies presenting similarities in electronic character and reactive nature between pairs. The current study extends the concept to systems of larger and varied composition as the pairs PdO+ and ZrO2+ as well as NiO+ and TiO2+ are interacted with C2H4 and CO through DFT calculations and guided-ion-beam mass spectrometry. It is determined that the pairs readily oxidize C2H4 while oxygen transfer is limited towards CO. Interestingly, within the reaction profiles for oxidation of C2H4 by PdO+ and NiO+, a spin crossover is observed which greatly increases the exothermicity of the process. This investigation presents a major step in identifying replacements for expensive group 10 metals in catalytic materials.
• Reactivity of stoichiometric titanium oxide cations. Tyo, Eric C.; Nőβler Melanie; Mitrić, Roland; Bonačić-Koutecký, Vlasta; Castleman Jr., A. W. (2011). 13(10) 4243–4249.

  We present the results of a reactivity study of titanium cationic clusters towards CO, C2H2, C2H4 and C3H6 based on guided-ion-beam mass spectrometry and DFT calculations. We identified Ti2O4+ and to a lesser extent TiO2+ species which preferentially undergo oxidation reactions. An oxygen centered radical of Ti2O4+ is responsible for selective oxidation. Energy profiles and MD simulations reveal the mechanisms of the reactions. Regeneration of the oxygen centered radical was achieved experimentally and theoretically through the reaction of N2O with Ti2O3+.
• Electronic Structure Similarities in PbxSby–and SnxBiy–Clusters. Melko, Joshua J.; Werner, Ute; Mitrić, Roland; Bonačić-Koutecký, Vlasta; Castleman, A. W. (2011). 115(37) 10276–10280.
• Field-induced surface hopping method for probing transition state nonadiabatic dynamics of Ag3. Mitrić, Roland; Petersen, Jens; Wohlgemuth, Matthias; Werner, Ute; Bonačić-Koutecký, Vlasta (2011). 13(19) 8690–8696.

  We present the simulation of time-resolved photoelectron spectra of Ag3 involving excitation from the linear transition state, where nonadiabatic relaxation takes place in a complex manifold of electronic states. Thus, we address ultrafast processes reachable by negative ion-to neutral-to positive ion (NeNePo) spectroscopy starting from the linear Ag−3 anionic species. For this purpose we use our newly developed field-induced surface hopping method (FISH) augmented for the description of photoionization processes. Furthermore we employ our method for nonadiabatic molecular dynamics “on the fly” in the framework of time-dependent density functional theory generalized for open shell systems. Our presented approach is generally applicable for the prediction of time-resolved photoelectron spectra and their analysis in systems with complex electronic structure as well as many nuclear degrees freedom. This theoretical development should serve to stimulate new ultrafast experiments.
• Tuning Cluster Reactivity by Charge State and Composition: Experimental and Theoretical Investigation of CO Binding Energies to AgnAum+/− (n + m = 3). Popolan, Denisia M.; Nössler, Melanie; Mitrić, Roland; Bernhardt, Thorsten M.; Bonačić-Koutecký, Vlasta (2011). 115(6) 951–959.
• Unique optical properties of silver cluster-biochromophore hybrids: Comparison with copper and gold. Kulesza, Alexander; Mitrić, Roland; Bonačić-Koutecký, Vlasta (2011). 501(4–6) 211–214.
• Investigating Reactive Superoxide Units Bound to Zirconium Oxide Cations. Tyo, Eric C.; Nossler, Melanie; Harmon, Christopher L.; Mitrić, Roland; Bonačić-Koutecký, Vlasta; Castleman, A. W. (2011). 115(44) 21559–21566.
• Simulation of laser-induced coupled electron-nuclear dynamics and time-resolved harmonic spectra in complex systems. Lisinetskaya, Polina G.; Mitrić, Roland (2011). 83(3)
• Time-dependent density functional theory excited state nonadiabatic dynamics combined with quantum mechanical/molecular mechanical approach: Photodynamics of indole in water. Wohlgemuth, Matthias; Bonačić-Koutecký, Vlasta; Mitrić, Roland (2011). 135(5)
• Structural and Optical Properties of Isolated Noble Metal–Glutathione Complexes: Insight into the Chemistry of Liganded Nanoclusters. Bellina, Bruno; Compagnon, Isabelle; Bertorelle, Franck; Broyer, Michel; Antoine, Rodolphe; Dugourd, Philippe; Gell, Lars; Kulesza, Alexander; Mitrić, Roland; Bonačić-Koutecký, Vlasta (2011). 115(50) 24549–24554.
• Simulation of time resolved photoelectron spectra with Stieltjes imaging illustrated on ultrafast internal conversion in pyrazine. Werner, Ute; Mitrić, Roland; Bonačić-Koutecký, Vlasta (2010). 132(17)
• Composition dependent adsorption of multiple CO molecules on binary silver–gold clusters AgnAum+ (n + m = 5): theory and experiment. Popolan, Denisia M.; Nößler, Melanie; Mitrić, Roland; Bernhardt, Thorsten M.; Bonačić-Koutecký, Vlasta (2010). 12(28) 7865–7873.

  The binding energies of multiple CO molecules to five-atom silver–gold cluster cations have been obtained employing temperature dependent gas phase ion trap measurements and ab initio calculations. The CO binding energies to AgnAum+ (n + m = 5) decrease with increasing number of silver atoms. Most strikingly, after the adsorption of the fourth CO to Au5+ and of the third CO to Ag5+, respectively, a pronounced decrease in the binding energies of further CO molecules was observed. This is related to a CO-induced structural transformation yielding more compact metal cluster geometries. First principles calculations revealed that the exact structure of the carbonyl complexes with multiple CO and the nature of the CO-induced structural transformation strongly depend on the composition of the metal cluster as well as on the number of adsorbed CO molecules.
• Experimental and theoretical study of the absorption properties of thiolated diamondoids. Landt, Lasse; Bostedt, Christoph; Wolter, David; Möller, Thomas; Dahl, Jeremy E. P.; Carlson, Robert M. K.; Tkachenko, Boryslav A.; Fokin, Andrey A.; Schreiner, Peter R.; Kulesza, Alexander; Mitrić, Roland; Bonačić-Koutecký, Vlasta (2010). 132(14)
• Time-Resolved Femtosecond Photoelectron Spectroscopy by Field-Induced Surface Hopping. Mitrić, Roland; Petersen, Jens; Wohlgemuth, Matthias; Werner, Ute; Bonačić-Koutecký, Vlasta; Wöste, Ludger; Jortner, Joshua (2010). 115(16) 3755–3765.
• Theoretical study of structural and optical properties of small silver and gold clusters at defect centers of MgO. Bürgel, Christian; Mitrić, Roland; Bonačić‐Koutecký, Vlasta (2010). 247(5) 1099–1108.
• How Shaped Light Discriminates Nearly Identical Biochromophores. Petersen, Jens; Mitrić, Roland; Bonačić-Koutecký, Vlasta; Wolf, Jean-Pierre; Roslund, Jonathan; Rabitz, Herschel (2010). 105(7)
• Non-adiabatic dynamics of pyrrole: Dependence of deactivation mechanisms on the excitation energy. Barbatti, Mario; Pittner, Jiří; Pederzoli, Marek; Werner, Ute; Mitrić, Roland; Bonačić-Koutecký, Vlasta; Lischka, Hans (2010). 375(1) 26–34.
• Ultrafast photodynamics of furan. Fuji, Takao; Suzuki, Yoshi-Ichi; Horio, Takuya; Suzuki, Toshinori; Mitrić, Roland; Werner, Ute; Bonačić-Koutecký, Vlasta (2010). 133(23)
• Doubly Charged Silver Clusters Stabilized by Tryptophan: Ag42+ as an Optical Marker for Monitoring Particle Growth. Kulesza, Alexander; Mitrić, Roland; Bonačić‐Koutecký, Vlasta; Bellina, Bruno; Compagnon, Isabelle; Broyer, Michel; Antoine, Rodolphe; Dugourd, Philippe (2010). 50(4) 878–881.
• Gas‐Phase Synthesis and Intense Visible Absorption of Tryptophan–Gold Cations. Antoine, Rodolphe; Bertorelle, Franck; Broyer, Michel; Compagnon, Isabelle; Dugourd, Philippe; Kulesza, Alexander; Mitrić, Roland; Bonačić‐Koutecký, Vlasta (2009). 48(42) 7829–7832.
• Generation of Oxygen Radical Centers in Binary Neutral Metal Oxide Clusters for Catalytic Oxidation Reactions. Nößler, Melanie; Mitrić, Roland; Bonačić‐Koutecký, Vlasta; Johnson, Grant E.; Tyo, Eric C.; Castleman, A. Welford (2009). 49(2) 407–410.
• Nonadiabatic Dynamics within Time-Dependent Density Functional Tight Binding Method. Mitrić, Roland; Werner, Ute; Wohlgemuth, Matthias; Seifert, Gotthard; Bonačić-Koutecký, Vlasta (2009). 113(45) 12700–12705.
• Optical and Structural Properties of Copper−Oxytocin Dications in the Gas Phase. Joly, Laure; Antoine, Rodolphe; Albrieux, Florian; Ballivian, Renaud; Broyer, Michel; Chirot, Fabien; Lemoine, Jérôme; Dugourd, Philippe; Greco, Claudio; Mitrić, Roland; Bonačić-Koutecký, Vlasta (2009). 113(32) 11293–11300.
• Clusters as model systems for investigating nanoscale oxidation catalysis. Johnson, Grant E.; Mitrić, Roland; Bonačić-Koutecký, Vlasta; Castleman, A.W. (2009). 475(1–3) 1–9.
• Laser-field-induced surface-hopping method for the simulation and control of ultrafast photodynamics. Mitrić, Roland; Petersen, Jens; Bonačić-Koutecký, Vlasta (2009). 79(5)
• Silver Cluster Chromophores for Absorption Enhancement of Peptides. Kulesza, Alexander; Mitrić, Roland; Bonačić-Koutecký, Vlasta (2009). 113(16) 3783–3788.
• Influence of Charge State on Catalytic Oxidation Reactions at Metal Oxide Clusters Containing Radical Oxygen Centers. Johnson, Grant E.; Mitrić, Roland; Nössler, Melanie; Tyo, Eric C.; Bonačić-Koutecký, Vlasta; Castleman, A. W. (2009). 131(15) 5460–5470.
• Absorption Enhancement and Conformational Control of Peptides by Small Silver Clusters. Tabarin, Thibault; Kulesza, Alexander; Antoine, Rodolphe; Mitrić, Roland; Broyer, Michel; Dugourd, Philippe; Bonačić-Koutecký, Vlasta (2008). 101(21)
• Nonadiabatic dynamics and simulation of time resolved photoelectron spectra within time-dependent density functional theory: Ultrafast photoswitching in benzylideneaniline. Mitrić, Roland; Werner, Ute; Bonačić-Koutecký, Vlasta (2008). 129(16)