A LOW-FREQUENCY INFRARED AND AB-INITIO STUDY OF THE REACTION OF TRICHLOROSILANE WITH SILICA

We investigate the adsorption of trichlorosilane (HSiCl3) on silica us ing infrared spectroscopy and examine the subsequent reactions of the chemisorbed species with water. Ab initio frequency calculations of mo del compounds that closely resemble the structure of possible surface species are used to aid in the assignment of infrared bands. The frequ ency of the Si-H stretching and bending modes of the chemisorbed HSiCl 3 is sensitive to the structure and is used in combination with the in formation obtained from the low frequency bands of the Si-Cl and Si-s- O-Si modes (Si-s refers to a surface Si atom) to obtain a clearer pict ure of the species formed on the silica surface.