Collisional narrowing of the vibrational Raman band of nitrogen and carbon monoxide

Abstract

Observations of the pressure narrowing of the vibrational Raman bands in N2 and CO are presented. For both gases a pressure of about 200 atm reduces the half-width of the bands by a factor 2. This behavior is explained in a semiquantitative way by the theory of motional narrowing. Motional narrowing occurs when the frequency of rotationally inelastic collisions reaches the magnitude of the frequency separation of the individual band components.