Infrared spectra of adsorbed molecules on thin silica films

Using a thin film of silica deposited on a ZnSe window we have been able to observe, after spectral subtraction, the i.r. spectra due to the SiOSi, SiOti, and SiOGa stretching modes when surface hydroxy groups react with (Me3Si)2NH, TiCl4, or GaMe3 respectively; this versatile technique permits rapid acquisition of i.r. spectral data, over a wide range of temperature or pressure, in regions where an oxide is strongly absorbing.