Knowledge Bank

When a mixture of $NO2$ with a large excess of neon is codeposited at approximately 5 K with a beam of neon atoms that has been excited in a microwave discharge, very prominent absorptions assigned to $v1$ of $NO2$+ and of $NO2\mathrm{<mrow\; data-mjx-texclass="ORD">-</mrow>}$ appear, as do weak absorptions assigned to the $(\nu 1+\mu 3)$ combination band of each of these ionic products. The product assignments are supported by detailed isotopic substitution studies, which also make possible normal coordinate analyses for these two species. The vibrational energy levels of $NO2\mathrm{<mrow\; data-mjx-texclass="ORD">+</mrow>}$ in a neon matrix are in good agreement with those recently $obtained2$ in a high resolution triple-resonant ionization study with zero kinetic energy photoelectron detection. When $O2$ is also present in the sample, the infrared-active stretching fundamental, $\nu 1(e\prime )$, of $NO3\mathrm{<mrow\; data-mjx-texclass="ORD">-</mrow>}$ appears. The cation field is sufficiently weak that splitting of the degeneracy is almost completely avoided.