Raman band shapes of simple molecules dissolved in liquid perfluorocompounds: Solute–solvent interaction study

Abstract

The vibrational Raman band shapes of N2, O2, and CO2 dissolved in perfluorotripropyl amine (FTPA), perfluorodecalin (FDC), and perfluorobenzene (FB) have been measured under elevated pressure (10–55 atm.). The full width at half-height (FWHH) of N2 and O2 vibrational spectra in the perfluoro-solvents increases with the order FTPA<FDC<FB. The vibrational bandwidths of the CO2 Fermi diad show explicit concentration dependence on these perfluoro-solvents. The FWHHs decrease with decreasing concentration. The anisotropic IVH band shape of CO2 ν1 mode in solution state, which tends to broadening when CO2 concentration decreases, is reported. The solvent and concentration dependences of the vibrational and rotational band shapes can be rationalized on the basis of cavity structure of the liquid perfluorocompounds and of no specific interaction between the solute and the solvent.