Knowledge Bank

Boron atoms from YAG laser ablation of the solid have been codeposited with Ar/$O2$ samples on a 12K salt window. The product infrared spectrum was dominated by 3 strong $11g$ isotopic bands at 1299.3, 1282.9 and $1274.6cm-1$ with $\mathrm{<mrow\; data-mjx-texclass="ORD">10</mrow>}B$ counterparts at 1347.6, 1330.7 and $1322.2cm-1$. Oxygen isotopic substitution ($\mathrm{<mrow\; data-mjx-texclass="ORD">16</mrow>}O18O$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}O2$) confirms the linear $BO2$ assignment of these strong bands. A sharp medium intensity band at 1854.7 has appropriate isotopic ratios for BO, which exhibits an 1862 $cm-1$ gas phase fundamental. A sharp $1931.0cm-1$ band shows isotopic ratios appropriate for another linear $BO2$ species; correlation with spectra of $BO2-$ in alkali halide lattices confirms this assignment. A weak $1898.9cm-1$ band grows on annealing and shows isotopic ratios for a BO stretching mode and isotopic splittings for 2 equivalent B and O atoms, which confirms assignment to $B2O2$. Weak 2062, 2048 and 2017 $cm-1$ bands grow markedly on annealing and show isotope shifts appropriate for a terminal -B0 group interacting with one other oxygen; these bands are assigned to $B2O3$ in agreement with the Weltner and White groups. The present experiments demonstrate that new boron-containing molecular species can be formed by matrix reactions of boron atoms and suitable molecules. These studies show that charged species can also be produced by pulsed laser ablation.