Coupling of molecular vibrons with contact phonon reservoirs

In this paper we describe a computational method for coupling localized molecular vibrations with contact phonons using a Green's function formalism. The phonon Green's function is constructed from the dynamical matrix of the contact -molecule-contact coupled system. Within this formalism we identify the imaginary part of the self-energy as the vibron lifetime for decay into contact phonons. This first-principles calculation allows us to compute the microscopic energy dissipation and the heat transport from the molecule to the contacts. This is a fundamental step for the evaluation of the power dissipated in molecular devices and for studying the thermal stability of molecular devices.