Knowledge Bank

The manifold of $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma g-$ vibronic levels of the $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}B1$ electronic state of $\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}NO2$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">15</mrow>}NO2$ observed by Douglas and $Huber1$ has been extended to lower energies and new observations added for $N18O2$. A potential function for the bending vibration of the excited state has been calculated using a Hamiltonian which employs a curvilinear bending $coordinate.2$ The potential function is approximately invariant to isotopic substitution and is well represented by a rapidly-converging Taylor series expansions about a linear equilibrium configuration. There is little or no evidence that the excited state equilibrium configuration is other than linear.