Knowledge Bank

Energy levels of nearly degenerated $\mathrm{<mrow\; data-mjx-texclass="ORD">5</mrow>}\Delta$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">5</mrow>}\Sigma$ states have been studied by the MR-SDCI + Q/Roos-ANO (or various combinations of other basis sets) method with Breit-Pauli Hamiltonian for relativistic effects and spin-orbit coupling interaction corrections. The $\mathrm{<mrow\; data-mjx-texclass="ORD">5</mrow>}\Sigma$ state has been predicted to be situated between $\mathrm{<mrow\; data-mjx-texclass="ORD">5</mrow>}\Delta 2$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">5</mrow>}\Delta 1$ substates, and hence the ground state is $\mathrm{<mrow\; data-mjx-texclass="ORD">5</mrow>}\Delta i$. Spectroscopic constants for $\mathrm{<mrow\; data-mjx-texclass="ORD">5</mrow>}\Delta$ state (and those for $\mathrm{<mrow\; data-mjx-texclass="ORD">5</mrow>}\Sigma$ state) are predicted as follows: $re=2.2047$ (1.9963) \AA; $B0=6043.2(6217.1)$ MHz; $D0=3.80(3.64)$ kHz; $\nu =510.4(543.9)cm-1$; $\mu e=5.92(4.88)D$.