Journal of Chemical Physics, Vol.114, No.11, 4955-4967, 2001
Quantum transport theory of vibrons in a molecular monolayer
We establish a quantum kinetic equation describing the transport properties of the vibrons in a molecular monolayer adsorbed on a dielectric substrate. A renormalization procedure is applied to the Hamiltonian of the system which is then separated in a vibron Hamiltonian, a bath Hamiltonian connected the external motions and a coupling Hamiltonian between the vibrons and the external modes. A perturbative analysis based on the projector method allows us to eliminate the irrelevant information related to the bath dynamics. The use of conventional approximations (Markov limit and Wick theorem) leads us to write the kinetic equation in a form exhibiting linear and nonlinear contributions. The linear term characterizes irreversible processes connected to the bath fluctuations whereas the nonlinear term represents a self-modulation of the dynamical matrix with respect to the vibron distribution. An application of the transport of CO vibrons on NaCl(100) illustrates the method. (C) 2001 American Institute of Physics.