Absolute Raman Scattering Cross-Section of Molecular Hydrogen

The absolute Raman scattering cross-section of H2 for the pure rotational lines and the Qbranch of the vibrational transition has been determined at the incident wavelengths 4800 and 5145 A. The absolute values were obtained by comparison to another Raman line, the 992 line of benzene, for which the cross-section had been determined by Kato and Takuma through absolute radiometric methods. Using the measured cross-sections which are estimated to be accurate to I 20 percent, we have determined the molecular polarizabilities Yoo and a01 to be Yoo = 0.362 x 10-24 cm2 and a01 = 0.137 x 10-24 cm2. The average cross-section for the Qbranch is 1.4 percent of the calculated Rayleigh cross-section while, at 294 K, the total rotational Raman cross-section for H2 gas is 2.7 percent of the calculated Rayleigh cross-section.