Hannover 2010 – scientific programme
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MO: Fachverband Molekülphysik
MO 3: Theory: Quantum Chemistry and Molecular Dynamics
MO 3.8: Talk
Monday, March 8, 2010, 18:30–18:45, F 102
On-The-Fly Computation of the Vibronic Spectrum of Formaldehyde — •Jörg Tatchen1 and Eli Pollak2 — 1Heinrich Heine University, Düsseldorf, Germany — 2Weizmann Institute of Science, Rehovot, Israel
Direct molecular dynamics without precomputed potential energy surfaces comprises a well-established tool in classical chemical reaction dynamics and nonadiabatic surface hopping. Developing analogous on-the-fly concepts for the true quantum regime where interference effects and tunneling are important is currently a very active area of research. In this work, we implement a semiclassical theory for the on-the-fly calculation of the S0 → S1 absorption band of formaldehyde. Time-dependent density functional theory is used for the S1 excited state potential energy surface. We obtain a reasonable description of the vibronic structure already from a frozen Gaussian theory using a few thousand trajectories.