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The Raman spectra of liquid and plastic CF4 and transition dipole–transition dipole interaction

1977; American Institute of Physics; Volume: 66; Issue: 7 Linguagem: Inglês

10.1063/1.434295

1520-9032

M. Gilbert, M. Drifford,

Solid-state spectroscopy and crystallography

The liquid and plastic phases of CF4 are investigated between 77 and 185 K. Little difference is found between the Raman spectrum of the liquid at the melting point and that of the plastic crystal. In the liquid, the strong infrared line ν3(f2) exhibits a complex Raman profile due to a large transition dipole–transition dipole interaction, similar to the LO–TO structure usually encountered in the Raman spectra of ionic crystals. An analysis of the various factors influencing the ν3 profile is outlined, and other possible cases of the occurrence of strong transition dipole–transition dipole interaction in liquids are cited. The other depolarized lines ν2(e) and ν4(f2) appear symmetrical, temperature sensitive, and are subject to weak vibrational relaxation. They provide precise information on rotations which is used in the analysis of previous NMR results of Rugheimer and Hubbard.