Critical effects on vibrational dephasing in CH 4 diluted in CO 2

Abstract

The Raman isotropic v 1 band of CH 4 diluted in CO 2 has been studied in the supercritical fluid phase, especially along the critical isochore of the mixture down to the liquid—vapour critical point. The comparison with published data on pure CH 4 shows that, in spite of the large vibrational band shift due to environmental fluctuations, the critical inhomogeneous broadening in the CH 4/CO 2 mixture is considerably attenuated.