Knowledge Bank

Pulsed-laser ablated beryllium atoms codeposited with $O2$ in excess argon at 10K yielded new beryllium-oxygen molecules. The initial reaction to make BeO is endothermic, but activation energy is provided by hyperthermal Be atoms. A strong band at $1572.9cm-1$ and weak hand at $396.9cm-1$ gave oxygen isotopic shifts consistent with a BeO diatomic molecule end are assigned to the $O2-BeO$ complex analogous to the Ar-BeO complex. A sharp band at $1413.2cm-1$ exhibited an oxygen isotopic triplet with $\mathrm{<mrow\; data-mjx-texclass="ORD">16,18</mrow>}O2$ and shifts appropriate for linear OBeO. A nearly coincident band at $1412.4cm-1$ gave an isotopic doublet and shifted in agreement with linear BeOBe. Quantum chemical calculations at the MBPT[2] level predict $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma$ ground stated and $\nu 3$ fundamentals at 1422.5 and $1418.2cm-1$ for OBeO and BeOBe, respectively, in excellent agreement with the observed values. Three bands at 1131.2, 866.3, and 522.4 $cm-1$ increased together on photolysis, yielded isotopic triplets, and agreed with MBPT[2] calculations for rhombic $Be2O2$. A sharp photosensitive band at 988.6 $cm-1$ gave oxygen isotopic shifts consistent with another linear OBeO species and is tentatively assigned to the molecular anion. An intense band at 1$465.1cm-1$ that appeared on annealing gave oxygen isotopic shifts in agreement with calculations for linear BeOBeO. Two hands at 1288.9 and $1264.1cm-1$ appeared on photolysis end gave isotopic triplets und shifts that are in excel lent agreement with calculations for branched $BeBeO2$. Annealing produced bands at 871.8 and $436.1cm-1$ that decreased on photolysis and are assigned to $BeO3$.