Motional Narrowing and Other Effects in the Q Branch of HD

Abstract

Observations of the Q(J) lines in the Raman spectrum of HD are reported for a range of densities at room temperature. The broadening of the individual components at low densities and the eventual overlap and collapse of the band at high densities is shown to be in agreement with the theory of motional narrowing of Alekseev and Sobel'man. A brief comparison of the broadening and shifting of the Q branch of HD with that for H2 is made.