THE INFRARED ABSORPTION SPECTRA OF $B_{2}O_{3}, B_{2}O_{2}$ AND $BO_{2}$ IN SOLID ARGON MATRICES
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Date
1962
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Ohio State University
Abstract
The infrared absorption spectra of $B_{2}O_{3}, B_{2}O_{2}$, and $BO_{2}$ isolated in solid argon matrices have been investigated in the region $350-4000 cm^{-1}$. The visible absorption spectrum of matrix isolated $BO_{2}$ was also observed in the region $4000-5500 {\AA}$. The molecules were generated in a high-temperature effusion cell and trapped under conditions of moderate to high dilution in solid argon matrices at approximately $4^{\circ}K$. Bands were found at 1955, 1921, 1899, 1323, and $1276 cm^{-1}$ in the spectra of $B_{2}^{10}O_{2}, B_{10}B_{11}O_{2}, B_{2}^{11}O_{2}$ and $B^{10}O_{2}$, and $B^{11}O_{2}$, respectively. For both $B_{2}^{10}O_{3}$ and $B_{2}^{11}O_{3}$ spectra of the most dilute matrices show seven distinct bands in the region $450-2100 cm^{-1}$. Six of these can be readily assigned as fundamentals and their relative intensities explained if the ''known V'' structure of $B_{2}O_{3}$ is supposed to have a larger apex angle than the reported, and the correlation of the normal vibrations and selection rules with those for the linear $D_{\infty h}$ model is considered. With additional help from the measured $B^{10}-B^{11}$ isotope shifts and force constant calculations the following complete assignment was obtained (all frequencies in $cm^{-1}$):$$\begin{array}{ll} B_{2}{^{10}}O_{3}:& [2128](a_{1}), 733(a_{1}), 536(a_{1}), [260](a_{1}); [480](a_{2}), 2128(b_{1}), 1242(b_{1}), 471(b_{1}); 493(b_{2})\\ B_{2}{^{11}}O_{3}:& [2060](a_{1}), 729(a_{1}), 518(a_{1}), [258](a_{1}); [460](a_{2}), 2060(b_{1}), 1239(b_{1}), 454(b_{1}); 477(b_{2})\end{array}$$ where the bracketed frequencies were not observed directly. Thermal functions have been computed for $B_{2}O_{3}$ and compared with the available calormetric data Structural parameters and a complete vibrational assignment have been estimated for $B_{2}O_{2}$. The infrared and green bands observed for $BO_{2}$ are in agreement with the high-resolution results of Johns. Thermal functions for $B_{2}O_{2}$ and $BO_{2}$ have also been computed.
Description
Author Institution: Department of Chemistry, The Ohio State university; Space Science Laboratory, General Electric Co.; Space Science Laboratory, National Bureau of Standards