“On the fly” semiclassical calculation of nonadiabatic spectra of pyrazine
Date | Fr, 14.02.2014 | |
Time | 14:00 | |
Speaker | Tomas Zimmermann, Laboratory of theoretical physical chemistry, EPFL | |
Location | ETH Zurich, Hönggerberg Campus, HIT F-12 | |
Program | In the first step, the multiple-surface dephasing representation (MSDR) is generalized to calculations of nonadiabatic electronic spectra. The resulting, rather crude, yet very efficient semiclassical method includes quantum effects through interference of mixed quantum-classical trajectories and through quantum treatment of the electronic degree of freedom. It requires very little computational effort in addition to the standard fewest switches surface hopping or Ehrenfest mean field dynamics and is very easy to implement. The method is tested by computing the absorption and time-resolved stimulated emission (TRSE) spectra of pyrazine using the four-dimensional three-surface model which allows for comparison with the numerically exact quantum result. Finally, the MSDR is combined “on the fly” with the SA-4-CASSCF(10,8)/6-31G* method to compute fully dimensional nonadiabatic spectra of pyrazine without approximations inherent to analytical models. The results for electronic absorption spectrum are compared with experiment. |
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Link | www.opteth.ethz.ch |