15min:
AN AB INITIO MOLECULAR ORBITAL STUDY OF LOW LYING ELECTRONIC EXCITED STATES OF FeC.

SACHIKO S. ITONO, TETSUYA TAKETSUGU, TSUNEO HIRANO, Department of Chemistry, Faculty of Science, Ochanomizu University, Tokyo 112-8610, Japan; UMPEI NAGASHIMA, National Institute for Advanced Interdisciplinary Research, Ibaraki 305-8562, Japan; K. AIUCHI, K. TSUJI AND K. SHIBUYA, Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo, 152-8551, Japan.

Spectroscopic constants and energy levels of the ground and low-lying excited states of iron carbide, FeC, have been calculated from potential energy functions obtained by the ab initio MR-SDCI molecular orbital approach. Investigated states are 1 Delta and 5 Pi, both of which are proposed by DF spectra as a candidate for the new Omega = 2 electronic state observed above the 3 Delta2 state by 3460 cm-1. The character of each electronic state has been discussed theoretically. Contrary to the previous tentative assignment to 5 Pi, the MR-SDCI results predict that the observed Omega = 2 state should be the 1 Delta state and be located at 3252 cm-1 above 3 Delta2. The spin-orbit coupling constant for 3 Delta state has also been calculated.