Vibrational Relaxation in Gases—Some Constraints on the Use of Master Equations

Abstract

The master equation for vibrational relaxation of diatomic dilute gases is derived. The derivation begins with the quantum Liouville equation and uses projection operator techniques; it can be extended to dense fluids under certain conditions. A careful discussion of the master equation's range of validity reveals restrictions on the experimental initial conditions and the relevant scattering cross sections.