Study of the temperature dependence of the mobility of methane adsorbed on NaA zeolite using infrared spectroscopy

Abstract

The ratio of the areas under the infrared bands v₁ and v₃ of methane adsorbed on NaA zeolite have been measured at different temperatures, in order to obtain information on the temperature dependence of the mobility of the methane molecule in the zeolite. Assuming that the intensity of the allowed v₃ band is independent of temperature, while the intensity of the forbidden v₁ band is proportional to the square of the inducing field, i.e. dependent on the position of molecules in the cavity, it is found that the variation with temperature of the intensity ratio reflects the temperature dependence of the mobility of the CH₄ molecules. The results are in agreement with neutron-scattering data.