Generalized quantum Fokker-Planck theory and its application to laser driven intramolecular hydrogen transfer reactions in condensed phases

A generalized quantum Fokker-Planck theory is proposed to treat the correla ted dynamics of coherent driving and Markovian dissipation. The resulting f ormulation is applicable to arbitrary external time-dependent driving field s and satisfies the detailed balance condition at arbitrary temperatures. A nalyzed are also the formal relations among the Caldeira-Leggett quantum Fo kker-Planck equation, the Bloch-Redfield theory, and the present formulatio n. The approach is numerically implemented to study the intramolecular hydr ogen transfer reaction dynamics in a one-dimensional model system. Differen t forms of external pulsed driving fields are exploited and their ability t o compete with concurring relaxation processes is investigated. Energy rela xation and pure dephasing are shown to have rather different influences on the reaction yield. (C) 2000 American Institute of Physics. [S0021-9606(00) 51114-3].