Semiclassical description of nonadiabatic quantum dynamics: Application to the S{sub 1}-S{sub 2} conical intersection in pyrazine
- Department of Chemistry, University of California, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
- Faculty of Physics, University Freiburg, D-79104 Freiburg, (Germany)
A recently proposed semiclassical approach to the description of nonadiabatic quantum dynamics [G. Stock and M. Thoss, Phys. Rev. Lett. 78, 578 (1997), X. Sun and W. H. Miller, J. Chem. Phys. 106, 916 (1997)] is applied to the S{sub 1}-S{sub 2} conical intersection in pyrazine. This semiclassical method is based on a transformation of discrete quantum variables to continuous variables, thereby bypassing the problem of a classical treatment of discrete quantum degrees of freedom such as electronic states. Extending previous work on small systems, we investigate the applicability of the semiclassical method to larger systems with strong vibronic coupling. To this end, we present results for several pyrazine models of increasing dimensionality and complexity. In particular, we discuss the quality and performance of the semiclassical approach when the number of nuclear degrees of freedom is increased. Comparison with quantum-mechanical calculations and experimental results shows that the semiclassical method is able to describe the ultrafast dynamics in this system. (c) 2000 American Institute of Physics.
- OSTI ID:
- 20216745
- Journal Information:
- Journal of Chemical Physics, Vol. 112, Issue 23; Other Information: PBD: 15 Jun 2000; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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