REACTIONS OF BORON ATOMS WITH MOLECULAR-OXYGEN - INFRARED-SPECTRA OF BO, BO2, B2O2, B2O3, AND BO2- IN SOLID ARGON

Boron atoms from Nd:YAG laser ablation of the solid have been codeposited with Ar/O2 samples on a 11 +/- 1 K salt window. The product infrared spectrum was dominated by three strong B-11 isotopic bands at 1299.3, 1282.8, and 1274.6 cm-1 with B-10 counterparts at 1347.6, 1330.7, and 1322.2 cm-1. Oxygen isotopic substitution (OO)-O-16-O-18 and O-18(2)) confirms the assignment of these strong bands to nu-3 of linear BO2. Renner-Teller coupling is evident in the nu-2 bending motion. A sharp medium intensity band at 1854.7 has appropriate isotopic ratios for BO, which exhibits a 1862.1 cm-1 gas phase fundamental. A sharp 1931.0 cm-1 band shows isotopic ratios appropriate for another linear BO2 species; correlation with spectra of BO2- in alkali halide lattices confirms this assignment. A weak 1898.9 cm-1 band grows on annealing and shows isotopic ratios for a BO stretching mode and isotopic splittings for two equivalent B and O atoms, which confirms assignment to B2O2. A weak 2062 cm-1 band grows markedly on annealing and shows isotope shifts appropriate for a terminal-BO group interacting with another oxygen atom; the 2062 cm-1 band is assigned to B2O3 in agreement with earlier work. A strong 1512.3 cm-1 band appeared on annealing; its proximity to the O2 fundamental at 1552 cm-1 and pure oxygen isotopic shift suggest that this absorption is due to a B atom-O2 complex.