DENSITY EFFECTS ON ROTATIONAL SECOND MOMENTS

Abstract

The Raman spectra of liquid $CHCl_{3}, CDCl_{3}$ and $SF_{6}$ have been measured as a function of density and temperature. For chloroform we have used the $\nu_{1}$ mode band and for $SF_{6}$. the $\nu_{2}$. mode band. The rotational second moments show a definite decrease with increasing density. This observation is in contrast to current theoretical views on the invariance of the ratational second moments with density. These density effects may be interpreted by including three and four particle correlations and considering cancellation effects between pairwise, triplet and quadruplet terms at high densities.""