Theoretical study of the electronic spectrum of the SiC- anion

The potential energy curves of the X(2)Sigma(+), A(2)II, and B(2)Sigma(+) s tates of the SiC- anion and of the (XII)-I-3 state of SiC have been calcula ted at the internally contracted multireference configuration interaction ( CMRCI) level with Dunning's augmented correlation-consistent polarized vale nce quadruple-zeta(-) (aug-cc-pVQZ) basis set. The equilibrium bond lengths (r(e)), harmonic frequencies (omega(e)), first-order anharmonicity constan ts (omega(e)x(e)), rotational constants (B-e), dipole moments (mu(e)), and dissociation (D-e) and excitation (T-e) energies for these states have been calculated. Core-correlation effects have been studied on both the X(2)Sig ma(+) ground state and first excited A(2)II State of SiC-. The spectroscopi c constants of the A(2)II and B(2)Sigma(+) states of SiC- and of the (XII)- I-3 state of SiC are in good agreement with available experimental data. Ad iabatic and vertical electron affinities (EA) of SiC((XII)-I-3) have also b een computed at the CMRCI/aug-cc-pVQZ level. The electronic transition mome nt functions (ETMFs) for both the B(2)Sigma(+)-(XC+)-C-2 and B(2)Sigma(+)-A (2)II transitions have been calculated at the CMRCI/aug-cc-pVQZ level. Base d on both the calculated potential energy curves and the transition moments , the radiative lifetimes of the B(2)Sigma(+)(v'=0-10) states have been com puted.