Peak and total differential Raman scattering cross sections for several liquids, CH3OH, C2H5OH, i-C3H7OH, (CH3)2CO, CH3CCl3, CH3I, c-C6H12, and C6H5Br, were determined relative to the v2 (a1g)=944 cm−1 line of C6D6 as an internal standard. Using an absolute value for the peak differential cross section of this line and measured values of the radiant intensities and depolarization ratios of selected Raman lines in the above liquids, we have obtained absolute values for ∂σ and ∂σ/∂Ω. Results are expected to be accurate to ± 10 % unless specified otherwise. Measurements were made using a medium power cw argon ion laser operating at 4880 Å, a double monochromator and a photomultiplier (S-20 and S-11) detector.

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The problem of measuring equilibrium vibrational temperatures in materials by using Raman spectroscopy has been analyzed theoretically and experimentally. One major problem is the determination of the corrections, due to the Raman instrument response, that must be applied to raw data to obtain the temperature. Normally a “standard” lamp is used for this purpose but the problems that can arise are legion. Methods for determining spectral response and temperature response function corrections that must be applied to raw Raman data, for ultimately deriving the equilibrium temperatures of various materials, have been developed such that standard lamps are not required. Instead pure vitreous silica and liquid cyclohexane, which are both readily available in all spectroscopy laboratories, are selected as reference materials of choice for determining the appropriate spectral corrections applicable to the spectrophotometric data. The results were tested against data obtained from other transparent materials, namely CCl4, CHCl3, CH3PCl2, GeCl4, GeBr4, and CS2. GeBr4 and CS2 were poor choices because of the proximity of the melting point of the former to room temperature and laser-induced photolysis of the latter. Detailed statistical analyses of the results indicate a marked lowering of systematic errors over those yielded by standard lamp calibrations. Shortcomings of both methods are also discussed, including several lesser known spectral abnormalities arising from the use of a standard lamp.

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