Raman spectra of fluid nitrogen: intermolecular torques and orientational correlation times

A comparison is made between the rotovibrational Raman bands of fluid nitrogen at room temperature in the 180–355 amagat density range and the corresponding pure rotational bands reported previously. Accurate moment values are derived from the Raman spectra, accounting for the response of the entire experimental apparatus, after subtraction of the unwanted isotope band and of the leaking polarized Q branch. Correlation times are also calculated for both rotovibrational and pure rotational spectra accounting for the finite instrumental slitwidth.

Intermolecular torques and orientational correlation times derived from the two spectra are in good agreement for almost the entire available density range. Small discrepancies, particularly evident in the low density correlation times, are discussed and related to the rotation-vibration interaction. Intermolecular correlations are found to be negligible.