ELECTRONIC STATES AND NATURE OF BONDING IN THE MOLECULE MOC BY ALL-ELECTRON AB-INITIO CALCULATIONS

Citation
I. Shim et Ka. Gingerich, ELECTRONIC STATES AND NATURE OF BONDING IN THE MOLECULE MOC BY ALL-ELECTRON AB-INITIO CALCULATIONS, The Journal of chemical physics, 106(19), 1997, pp. 8093-8100
Citations number
15
Categorie Soggetti
Physics, Atomic, Molecular & Chemical
ISSN journal
00219606
Volume
106
Issue
19
Year of publication
1997
Pages
8093 - 8100
Database
ISI
SICI code
0021-9606(1997)106:19<8093:ESANOB>2.0.ZU;2-E
Abstract
In the present work all electron ab initio multiconfiguration self-con sistent-held (CASSCF) and multireference configuration interaction (MR CI) calculations have been carried out to determine the low-lying elec tronic states of the molecule MoC. The relativistic corrections for th e one electron Darwin contact term and the relativistic mass-velocity correction have been determined in perturbation calculations. The elec tronic ground state is predicted as (3) Sigma(-). The spectroscopic co nstants for the (3) Sigma(-) electronic ground state and eight low-lyi ng excited states have been derived by solving the Schrodinger equatio n for the nuclear motion numerically. Based on the results of the CASS CF calculations the (3) Sigma(-) ground state of MoC is separated from the excited states (3) Delta, (5) Sigma-, (1) Sigma, (1) Delta, (5) P i, (1) Sigma(+), and (3) Pi by transition energies of 4500, 6178, 7207 , 9312, 10 228, 11 639, and 16 864 cm(-1), respectively. The transitio n energy between the (3) Sigma(-) ground state and the (3) Pi state as derived in the MRCI calculations is 15 484 cm(-1). For the (3) Sigma( -) ground state the equilibrium distance has been determined as 1.688 Angstrom, and the vibrational frequency as 997 cm(-1). The chemical bo nd in the (3) Sigma(-) electronic ground state has triple bond charact er due to the formation of delocalized bonding rr and a orbitals. The chemical bond in the MoC molecule is polar with charge transfer from M o to C, giving rise to a dipole moment of 6.15 D at 3.15 a.u. in the ( 3) Sigma(-) ground state. (C) 1997 American Institute of Physics.