Kinetics of Thermal Excitation of a Molecule in a Condensed Medium

A microscopic model of thermal excitation the vibrational ground state a molecule interacting with condensed medium is developed. The master equation for evolution occupancies levels derived. rate constant limiting process molecular determined analytically. It shown that while this quantity independent temperature at low temperatures, by coinciding speed limit quantum transitions due to uncertainty principle, it rises rather linearly high temperatures according Einstein's relation adiabatic transitions.