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 correlated dynamics of coherent driving and Markovian dissipation. The resulting formulation is applicable to arbitrary external time-dependent driving fields and satisfies the detailed balance condition at arbitrary temperatures. Analyzed are also the formal relations among the Caldeira–Leggett quantum Fokker– Planck equation, the Bloch–Redfield theory, and the present formulation. The approach is numerically implemented to study the intramolecular hydrogen transfer reaction dynamics in a one-dimensional model system. Different forms of external pulsed driving fields are exploited and their ability to compete with concurring relaxation processes is investigated. Energy relaxation and pure dephasing are shown to have rather different influences on the reaction yield. © 2000 American Institute of Physics. @S0021-9606~00!51114-3#