Knowledge Bank

The electronic spectrum of the neptunyl ion, $NpO22+$, has been calculated using relativistic spin-orbit configuration-interaction calculations. Neptunium in $NpO22+$ is in oxidation state VI and has an $f1$ configuration. In the lower energies lie the $f\to f$ transitions while at energies above $20000cm-1$ charge transfer transitions occur. The ground state is $a2\Delta$ state with $\Omega =3/2$. Equilibrium distances and vibrational frequencies for the symmetric stretch in the ground state are obtained and compared with experimental work.