Electronic Spectrum of Tin Oxide: MRDCI Study

Abstract

Multireference singles and doubles configuration interaction (MRDCI) calculations have been carried out to investigate the electronic structure and spectroscopic properties of the low-lying electronic states of tin oxide. A sufficiently large basis set with additional d and f polarization functions is employed. Potential energy curves of both spin-excluded and spin-included states, which correlate with the lowest dissociation limit Sn(3Pg)+O(3Pg), are reported. The computed spectroscopic properties of the electronic states below 40 000 cm-1, such as X1Σ+, a 3Σ+, b3Π, A1Π, E1Σ+, and their spin−orbit components, are compared with the observed results. The MRDCI estimated dissociation energy of the ground state of SnO is 5.03 eV taking the d-correlation into account. Effects of the d-electron correlation on the spectroscopic constants of the ground and a few low-lying Λ−S states have been explored. Transition probabilities of a few transitions are estimated. The A1Π−X and E1Σ+−X transitions are predicted to be quite strong. The spin-forbidden transitions such as b3Π1−X and b 3Π0+−X are compared with the Cameron band of the isovalent CO molecule. The calculated dipole moments of SnO as a function of the bond length in three low-lying states, namely X1Σ+, A1Π, and E1Σ+, have been reported.