Ab initio study of the electronic spectrum of the SiN radical

Abstract

The potential energy curves of the SiN radical for the low-lying electronic states correlating up to the fourth dissociation channel have been calculated at the internally contracted multireference configuration interaction (CMRCI) level with Dunning's correlation-consistent polarization valence triple zeta (cc-pVTZ) basis set. The equilibrium bond length (r(e)), harmonic frequency (w(e)), first-and second-order anharmonicity constants (w(e)x(e), w(e)y(e)), rotational constant (B-e), centrifugal distortion constant (D-e), and rotation-vibrational and centrifugal coupling constants (alpha(e) and beta(e) respectively), as well as the dipole moment (mu(0)), excitation (T-e), and dissociation energies (D-0) for the 11 bound doublet states X-2 Sigma(+), A(2) Pi, B-2 Sigma(+), C-2 Pi, D-2 Sigma(-), E-2 Delta, F-2 Pi, G(2) Delta, H-2 Sigma(+), I-2 Phi, and J(2) Pi and 10 bound quartet states a(4) Sigma(+), b(4) Pi, c(4) Delta, d(4) Sigma(-), e(4) Sigma(+), f(4) Sigma(-), h(4) Delta, i(4) Sigma(+), j(4) Pi, and k(4) Delta have been calculated at the CMRCI level with Dunning's correlation-consistent polarization valence quadruple zeta (cc-pVQZ) basis set. Our calculations imply that the D-2 Pi and L-2 Pi states in the literature should be reassigned as C-2 Pi and F-2 Pi, respectively. Where available, our results are found to be in good agreement with the experimental data. (C) 1998 Academic Press.