MOLECULAR-DYNAMICAL CALCULATIONS OF THE VIBRATIONAL-SPECTRA OF HYDROCARBONS ADSORBED IN SILICALITE

The density of vibrational states, infrared and Raman spectra of metha ne, ethane, propane, ethene and ethyne adsorbed in silicalite are calc ulated by molecular dynamics techniques assuming flexible molecules in a rigid zeolite framework. Small frequency shifts, intensity variatio ns and band broadening are observed by comparison with the spectra of the free molecules calculated with the same technique. The low-frequen cy spectra can be interpreted in terms of rigid entities floating in t he zeolite channels.