Quantum mechanical studies of proton transfer in condensed phase

Abstract

Theoretical studies of proton transfer in condensed phase are presented. Three particular issues have been addressed: the effect of anharmonicity of the bath modes, the role of coupled nonreactive motions in laser control of proton transfer, and a quantum Kramers calculation of the rate of intramolecular proton transfer in glycine. The modulation of proton tunneling dynamics by anharmonic modes in the environment has been investigated using an operator resummation method. Anharmonicity in the coupled modes is found to increase the rate of proton transfer by enhancing the tunneling rate. In the study on laser control, it is found that coupling the environmental modes to the external field has significant effects on the efficiency of control. It is also seen that small perturbations in the laser control waveforms affect the efficiency of control. A first principles study of intramolecular proton transfer in the amino acid glycine is undertaken by solving the quantum Kramers problem in the Miller-Schwartz-Tromp formalism. The rate for intramolecular proton transfer is calculated and found to be in good agreement with the experimental result.