Keywords: 
• 爱因斯坦系数 /
• 弗兰克-康登因子 /
• 辐射寿命 /
• 势能函数

Abstract: Low-lying electronic states (X2Π, A2Σ+, a4?, B2?, b4Π, C2Π, F2Σ?, E2Σ+ and D2Π) of the 6Li32S molecule are computed at the aug-cc-pV5Z/MRCI level. The potential energy curves are presented for these states;the corresponding spectroscopic constants are reported. Electronic transition moment, Einstein coe?cients, Frank-Condon factors and radiative lifetimes for the A2Σ+-X2Π, B2?-X2Π, C2Π-X2Π systems are calculated. The balanced distance between two nuclei, harmonic frequencies and inertia moment of ground state X2Π are predicted in this paper, and they are in accordance with their corresponding experimental data. The balance distances between the two nuclei in the electronic states of b4Π, C2Π, D2Πare all longer than 4 ?, so they are very unstable. The D2Πelectronic state will dissociate to Li+ ion and S? ion: they are far from each other. The electronic transition dipole moment, Einstein coefficient, Franck-Condon factor and radiative lifetime in transition from lowest excited A2Σ+ state to ground state X2Π are predicted in this paper. The electronic transition dipole moments from three low lying electronic state A2Σ+, B2? and C2Π to the ground state X2Π are calculated at the aug-cc-pV5Z/MRCI level. The results show that the electronic transition dipole moment of A2Σ+ → X2Π has a small positive value while the nucleus distance is short, and rapidly decreases down to a small negative value with the nucleus distance increasing to around balance distance. Then it is stable about zero value while the nucleus distance continually increases. The electronic transition dipole moment of B2?→X2Πhas a small negative value (which is larger than that of A2Σ+ →X2Π) at a short nucleus distance, and rapid increases up to a small positive value with the nucleus distance increasing to about balance distance. Then it slows down to zero while the nucleus distance increases to about 4 ?. Finally it turns stable about zero value while the nuclei distance continually increases. The electronic transition dipole moment of C2Π→X2Π is more sophisticated, but it has a large value than other two transitions. So the low-lying electronic state A2Σ+ is stabler than B2?, and B2? is stabler than C2Π. The results also show that the ground state X2Π and the lowest excited state A2Σ+ have similar IR frequencies, their difference is within 8 cm?1, so they cannot be distinguished by IR spectrum. The A2Σ+ has a balanced distance about 0.076 ? shorter than ground X2Π, which implies that A2Σ+ has stronger chemical bond than ground X2Π.