
Accession Number : AD0634437
Title : POPULATION DISTRIBUTIONS DURING VIBRATIONAL RELAXATION OF DIATOMIC GASES,
Corporate Author : CORNELL AERONAUTICAL LAB INC BUFFALO N Y
Personal Author(s) : Rich, J. W. ; Rehm,R. G.
Report Date : APR 1966
Pagination or Media Count : 32
Abstract : A master equation analysis for the vibrational relaxation of a diatomic gas is presented, including the effects of nearresonance exchange of vibrational energy between colliding oscillators. It is found that the mechanism of rapid nearresonance exchange of vibrational energy among the diatomic species tends to maintain a quasisteady state vibrational population distribution during the relaxation of a pure gas. The specific functional form of this quasisteady state distribution is determined from a perturbation analysis of the master equation. A detailed analyses is also given of the relaxation equations for the case of equidistant vibrational energy level spacing. It is found that when the diatomic gas is diluted by an inert to the extent that oscillatoroscillator exchange collisions no longer influence relaxation, the vibrational population distribution can depart markedly from the Boltzmann form. Whenever exchange collisions predominate, however, it is found that a nearBoltzmann distribution is preserved, regardless of the form of the vibrationtranslation transition probabilities, and the energy relaxation equation does not differ greatly from the LandauTeller result. (Author)
Descriptors : (*DIATOMIC MOLECULES, RELAXATION TIME), (*MOLECULAR ENERGY LEVELS, STATISTICAL DISTRIBUTIONS), VIBRATION, EXCITATION, EQUATIONS, PERTURBATION THEORY
Subject Categories : Atomic and Molecular Physics and Spectroscopy
Quantum Theory and Relativity
Distribution Statement : APPROVED FOR PUBLIC RELEASE