Isotropic collision-induced scattering by CF4 in a Raman vibrational band

Light-scattering intensities and depolarization ratio data have been recorded at room temperature for gaseous tetrafluoromethane in the collision-induced band of the Raman vibrational line nu(1) = 908 cm(-1). For the first time, binary isotropic intensities of the nu(1)-Raman band are reported in absolute units for Stokes frequency shifts up to 110 cm(-1). From comparison with theoretical semiclassical computations of the dipole-multipole spectrum contributions, evaluations of the first derivatives of the successive dipole-multipole polarizability tensors are provided. These results are coherent with those obtained from corresponding depolarized intensities. Moreover, the agreement with ab initio quantum-chemistry calculations of the CF4 multipolar polarizabilities is satisfactory. (C) 1999 American Institute of Physics. [S0021-9606(99)52522-1].