15min:

QIANG CHANG AND RUSSELL M. PITZER, Department of Chemistry, The Ohio State University, Columbus, OH 43210.

Ab initio spin-orbit configuration interaction calculations are performed on the UO₂ molecule, which has been observed in matrix isolation and vacuum ultraviolet spectroscopic studies. UO₂ is isoelectronic with PuO₂²⁺, which has a 5f ¹ 5f ¹~³H_4g ground state. We find, as have other workers, that UO₂ has a 5f ¹ 7s ¹~ ³ ₂ ground state with a moderate mixture of 5f ¹7s ¹~ ³ ₂. the UO distance is found to be 1.786 \dotA. The ³H_4g state is only slightly higher in energy. Oscillator strengths have been calculated for electronic transitions.