TCBG Seminar

Reaction Rates and Raman Spectra of Double Well Tunneling Systems in Condensed Phases

Professor Yoshitaka Tanimura
Institute for Molecular Science and the Graduate University for Advanced Studies
Okazaki, Japan


Monday, March 13, 2000
3:00 pm (CT)
2269 Beckman Institute


A Fokker-Planck equation is derived for a quantum mechanical particle moving in arbitrary potentials and being strongly coupled to a low temperature heat-bath described by Gaussian-Markovian like noise. This equation is expressed in the form of a differential equation acting on the Wigner distribution of the particle and reduces to the Newton equation in the classical limit. The theory developed is applied to the case of hydrogen tunneling in a double well potential and reaction rates as well as Raman spectra are determined. Reaction rates are calculated by means of a linear response simulation in which a perturbation is applied that destabilizes one well. Rates calculated in the framework of the quantum treatment are much larger than those determined in the classical limit due to tunneling. Resonant oscillations are also observed in the quantum case. Raman spectra are calculated using the Louiville time evolution expression for the two-time correlation function of the coordinate. In these spectra a tunneling peak appears in the quantum case at very low frequency.

Tea and coffee will be served in R3151 Beckman Institute at 2:15pm.

Main TCBG Seminars page