Diffuse reflectance Fourier-transform infrared studies of hydrogen adsorbed on sodium zeolites

Abstract

Crystal-field-induced infrared spectra of hydrogen adsorbed on various sodium zeolites have been recorded at room temperature and 77 K, respectively, by means of the diffuse reflectance technique. The deep-bed treated samples (Na-ZSM-5, Na-Mordenite, Na-Y, Na-X, Na-A) were contained in sealed quartz glass ampoules. The dependence on the H₂ concentration, bandshape and position of the hydrogen fundamentals and overtones are discussed in comparison with results of former studies. The fundamental of hydrogen molecules adsorbed on Na⁺ at S_ii sites in Na-Y could be shown to be ortho–para-split by 5.8 cm^–1 The same rotational fine structure has been observed in the overtone spectrum.