MATRIX ISOLATION INFRARED OBSERVATION OF THE HSiN$_{2}$ AND H$_{2}$SiN$_{2}$ COMPLEXES USING A 121 NM VACUUM-ULTRAVIOLET PHOTOLYSIS SOURCE
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Date
2008
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Publisher
Ohio State University
Abstract
Matrix isolation infrared spectroscopy was used to characterize the complexes of H$_{2}$Si and HSi with N$_{2}$ that result from the vacuum-ultraviolet photolysis of silane (SiH$_{4}$) in cryogenic nitrogen (N$_{2}$) matrices. Experiments were performed by depositing mixtures of SiH$_{4}$ with N$_{2}$ onto a CsI window at 12 K while simultaneously photolyzing the mixture with 121 nm vacuum-ultraviolet radiation from a hydrogen resonance lamp. The infrared bands of the H$_{2}$SiN$_{2}$ complex observed in these experiments are the N-N stretching mode at 2274.2 cm$^{-1}$ and the H$_{2}$Si asymmetric and symmetric stretching modes at 2013.6 and 2009.4 cm$^{-1}$, respectively. The infrared bands of the HSiN$_{2}$ complex observed in these experiments are the N-N stretching mode at 2023.9 cm$^{-1}$, the Si-H stretching mode at 2006.6 cm$^{-1}$, and the H-Si-N bending mode at 813.7 cm$^{-1}$. The assignment of these bands to the H$_{2}$SiN$_{2}$ and HSiN$_{2}$ complexes is established by performing experiments with isotopic reagents (SiD$_{4}$, $^{15}$N$_{2}$), by performing matrix annealing experiments (warming to 20 - 30 K and refreezing to 12 K), by performing mercury-xenon lamp matrix photolysis experiments, and by comparison to density functional theory calculations at the B3LYP/aug-cc-pVTZ level.
Description
Author Institution: School of Science, Penn State Erie, Erie, PA 16563