Time-averaging approximation in the interaction picture: anisotropy of vibrational pump-probe experiments for coupled chromophores with application to liquid water.
A time-averaging approximation method developed to efficiently calculate the short-time dynamics of coupled vibrational chromophores using mixed quantum/classical theories is extended in order to be applicable to the study of vibrational dynamics at longer time scales. A quantum mechanical time propagator for long times is decomposed into the product of short-time propagators, and a time-averaging approximation is then applied to each of the latter. Using the extended time-averaging approximation, we calculate the anisotropy decay of the data obtained from impulsive vibrational pump-probe experiments on the OH stretching modes of water, which is in excellent agreement with numerically exact results.
Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 361-763, South Korea. minoyang@chungbuk.ac.kr
Mino
M
Yang