ABSOLUTE RAMAN CROSS-SECTIONS FOR CYCLOHEXANE, ACETONITRILE, AND WATER IN THE FAR-ULTRAVIOLET REGION

Absolute Raman cross sections with excitation at wavelengths between 266 and 200 nm have been determined for the CH and CN stretching modes of acetonitrile, the symmetric OH stretch of water, and the CH stretches of cyclohexane. The measurements have been performed both directly, using an integrating cavity method, and indirectly, by reference to methane gas as an external standard. The two methods agree to within 35% or better in all cases. The cross sections are fit to Albrecht A-term frequency dependences to permit interpolation and modest extrapolation from the measured points. These solvent Raman bands can now be employed as internal standards for the determination of absolute resonance Raman cross sections of solutes in the far-UV spectral region. © 1990 American Chemical Society.