Theoretical study on lower electronic states of the FeSi molecule

Abstract

The low lying electronic states of the FeSi molecule have been investigated by performing complete active space self-consistent field (CASSCF) and multireference single and double excitation configuration interaction (MRSDCI) calculations. Although the classification of the ground state was not established, the results of the MRSDCI calculations suggest that the ground state of FeSi is 3Δ, and the lowest excited state is 5Π whose transition energy is 0.36 eV including the Davidson-type Q correction. The R e given by MRSDCI with Q correction is 2.23 Å for 3Δ and 2.19 Å for 5Π. The spectroscopic constants and dipole moments of the low lying 5Δ and 3Π states as well as the 3Δ and 5Π states are also evaluated. The bonding nature of FeSi in the 3Δ state is discussed in comparison with the FeC molecule. © 2003 Taylor & Francis Group, LLC.