Knowledge Bank

The NbO molecule has been trapped in neon and argon matrices at $4\circ K$ and investigated by ESR and optical spectroscopy. Analysis of the observed ESR spectra show that NbO has a $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Sigma -$ electronic ground state derived from a $\sigma 1\delta 2$ configuration. Hyperfine constants due to interaction with $\mathrm{<mrow\; data-mjx-texclass="ORD">93</mrow>}Nb$ (I = 9/2) and g tensor elements have been determined. In neon these magnetic parameters are $g\parallel =2.002,g\perp =1.958,A\parallel =1586.5$ MHz, and $A\perp =1646.6$ MHz. Both Nb $\mathrm{<mrow\; data-mjx-texclass="ORD">16</mrow>}O$ and Nb $\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}O$ have been studied optically. The $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Sigma -$ - $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Sigma -$ blue system of NbO appears at 461.4 nm (in Ne) while additional systems, possibly $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Pi$ - $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Sigma -$, appear in the red. The vibrational frequency of ground state Nb $\mathrm{<mrow\; data-mjx-texclass="ORD">16</mrow>}O$ (in Ne) is observed at $977.2cm-1$ in the infrared.