Berlin 2014 – scientific programme

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MO: Fachverband Molekülphysik

MO 9: Theory 2: Molecular Dynamics & Quantum Chemistry

MO 9.1: Talk

Tuesday, March 18, 2014, 14:00–14:15, BEBEL SR144

Simulation of time-resolved pump-probe IR spectra — •Matthias Wohlgemuth and Roland Mitric — Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Würzburg, Deutschland

We present a new approach for the simulation of time-resolved pump-probe infrared (TRIR) spectra based on the molecular dynamics (MD) "on-the-fly". The simulations are carried out in the frame of density functional theory and have been combined with the Wigner phase space approach for the simulation of pump-probe spectra.

Our method was applied to the C=O to N-H water migration motion around a peptide linkage, which is observed by experimental TRIR spectroscopy. Our simulations reproduce all details of the measured time-resolved infrared spectra. The simulations show two concurrent mechanisms involved in the migration process, which were previously not derived from conventional stand-alone MD simulation and the simple experimental interpretation based on classical rate-equation analysis.

Altogether, our methods are uniquely suitable for the simulation of TRIR spectra in complex systems and provide a valuable help in the interpretation of the state-of-the-art experiments and it emphasizes the importance of the theoretical validation of TRIR experiments.