Theoretical Study of the Electronic Spectrum of the SiC-Anion

Abstract

The potential energy curves of the X2Σ+, A2Π, and B2Σ+ states of the SiC- anion and of the X3Π state of SiC have been calculated at the internally contracted multireference configuration interaction (CMRCI) level with Dunning's augmented correlation-consistent polarized valence quadruple-ζ (aug-cc-pVQZ) basis set. The equilibrium bond lengths (re), harmonic frequencies (ωe), first-order anharmonicity constants (ωexe), rotational constants (Be), dipole moments (μe), and dissociation (De) and excitation (Te) energies for these states have been calculated. Core-correlation effects have been studied on both the X2Σ+ ground state and first excited A2Π state of SiC-. The spectroscopic constants of the A2Π and B2Σ+ states of SiC- and of the X3Π state of SiC are in good agreement with available experimental data. Adiabatic and vertical electron affinities (EA) of SiC(X3Π) have also been computed at the CMRCI/aug-cc-pVQZ level. The electronic transition moment functions (ETMFs) for both the B2Σ+−X2Σ+ and B2Σ+−A2Π transitions have been calculated at the CMRCI/aug-cc-pVQZ level. Based on both the calculated potential energy curves and the transition moments, the radiative lifetimes of the B2Σ+(v‘=0−10) states have been computed.