Matrix-Isolation Study of the Vacuum–Ultraviolet Photolysis of Dischlorosilane. The Infrared Spectrum of the Free Radical SiCl2

In studies of the vacuum–ultraviolet photolysis of SiH2Cl2 and of SiD2Cl2 suspended in an argon matrix at 14°K, new absorptions appear at 502 and at 513 cm−1 which may be assigned as the two stretching fundamentals of SiCl2. A broad, unstructured absorption is also observed in the region of the ultraviolet spectrum in which features tentatively ascribed to SiCl2 were observed in earlier gas-phase emission studies. The detailed assignment of the observed infrared features is considered, and values of the valence angle, the Si–Cl stretching force constant, and the stretching–interaction force constant are estimated, corresponding to the two possible assignments for the infrared absorptions.