Normal coordinate analysis of molecules adsorbed on zeolite surfaces. Part 1.—Cyclopropane adsorbed on sodium faujasites and mordenites

Abstract

Vibrational analysis of adsorbed polyatoms provides valuable information on the degree of participation of different bonds in the interaction with the adsorbent. As an example, normal coordinate analysis has been applied to cyclopropane in the free and the adsorbed state in sodium faujasites and mordenites of different Si/Al ratios using a valence force field. The alterations of the force constants can be interpreted in terms of changes of the molecular geometry and electronic structure as well as by the hindrance of the bending motion due to the interaction with the internal surface. The lack of influence of the lattice module supports the location of the cyclopropane molecule near the cations.