Raman study of molecular reorientation in liquid chloroform and chloroform-<i>d</i> under high pressure

Abstract

The molecular reorientation in liquid chloroform and chloroform-d has been studied as a function of temperature and pressure by analysis of the Raman line shapes for the ν1(A1) C–H and C–D stretching modes at 3020 and 2256 cm−1, respectively. The measurements cover the temperature range 303–363 °K and the pressure range 0.03–4.5 kbar. Analysis of the Raman bands yields the reorientational correlation times τϑ, and the reorientational correlation functions under isobaric, isothermal, and isochoric conditions. The τϑ’s show a good agreement with the correlation times obtained from NMR relaxation measurements. The results on rotational second moments MR(2) provide experimental evidence that the rotational second moments are density dependent. In addition, the experiments indicate that collisional induced scattering contributes in a major way to the observed MR(2). Comments on the different peak positions for the IVV and IVH bands are also included.