VAPOR-LIQUID SHIFTS IN LASER RAMAN SPECTRA OF ORGANIC COMPOUNDS

Author Institution: Bartlesville Energy Research CenterThe calculation of thermodynamic functions for the vapor state by methods of statistical thermodynamics requires molecular spectra for the vapor state. Potentially, laser Raman spectra of vapors could provide information to supplement that obtained from infrared spectra, including far-Infrared spectra. However, the low vapor pressure of many organic compounds of interest precludes obtaining vapor-state Raman spectra at ambient temperature. With a heated cell to provide sufficiently high vapor concentration in the exciting beam. Satisfactory Raman spectra are being obtained for the vapors of less-volatile compounds. Comparisons with the Raman spectra for the liquid state show the shifts of low-wave number fundamentals expected from previous experience with far-infrared spectra