Knowledge Bank

The low-lying excited states of CuCl have been investigated theoretically in the Hartree-Fock approximation. Spin-orbit interactions have been included semiempirically using an atoms-in-molecules technique. All six excited states that had previously been characterized mentally are found to arise from the fine-structure sub levels of the $Cu+(3d94s 1,3D)Cl-(3p6 1S)$ configuration. The Calculated energy separations nearly quantitatively reproduce those observed experimentally. These reassignments rationalize as well the excited states of CuF and presumably those of CuBr and CuI but Indicate that the A-doubling observed experimentally cannot be of the $p\Pi /p\sigma$ ``pure precession’’ type as previously assumed. However, preliminary calculations of the A-doubling constants are not completely consistent with the experimental observations.