Infrared Spectra of the Novel Si2H2 and Si2H4 Species and the SiH1,2,3 Intermediates in Solid Neon, Argon, and Deuterium

Laser-ablated silicon atoms react extensively with hydrogen to form the silicon hydrides SiH 1,2,3,4 and the disilicon hydrides Si 2 H 2,4,6 . Infrared spectra and density functional theory frequency calculations with HD and D 2 substitution are used to identify these species in solid neon, argon, and deuterium. The novel dibridged Si 2 H 2 species is characterized by an antisymmetric Si−H−Si stretching mode at 1100.3 cm -1 and the trans-folded Si 2 H 4 intermediate by antisymmetric SiH 2 stretching and bending modes at 2151.6 and 858.5 cm -1 in solid neon. The SiH 3 - anion is identified by photosensitive absorptions at 1856 and 1837 cm -1 in solid neon. Silicon atoms in pure deuterium gave primarily SiD 4 with some SiD 3, Si 2 D 6, and Si 2 D 4 and no evidence for SiD and SiD 2, but SiD 3 - and SiD 2 - were observed.