The electronic structures and spectroscopic properties of SnBr molecule are calculated by high-level multireference configuration interaction (MRCI) method. The Davidson correction (+Q) and spin-orbit coupling (SOC) effect are investigated in the calculations. The potential energy curves (PECs) of 23 Ʌ-S states and 45 Ω states generated from those Ʌ-S states are obtained. Based on the calculated PECs, the spectroscopic constants of the bound states are evaluated, which are in good accordance with previous experimental data. At the avoided crossing point, the dipole moments (DMs) of Ʌ-S states exhibit abrupt change, which are attributed to the change of electronic configurations of those states. With the help of the calculated SO matrix elements, the interaction between 1⁴Σ^- and nearby states is analyzed, and the possible predissociation pathway of low-lying vibrational levels of 1⁴Σ^- is illuminated. In the end, transition dipole moments (TDMs) and the radiative lifetimes from the excited states to the ground state are determined.

SnBr分子的电子结构和光谱特性是通过高级多参考配置相互作用（MRCI）方法计算的。在计算中研究了戴维森校正 (+Q) 和自旋轨道耦合 (SOC) 效应。获得了 23 个 Ʌ-S 状态和从这些 Ʌ-S 状态产生的 45 Ω 状态的势能曲线 (PEC)。基于计算的 PEC，评估了束缚态的光谱常数，这与之前的实验数据非常吻合。在避免的交叉点处，Ʌ-S状态的偶极矩（DM）表现出突变，这归因于这些状态的电子配置的变化。借助计算的 SO 矩阵元素，1 ⁴ Σ ^{-分析了附近的状态，阐明了1 4} Σ ^-低振动能级可能的预解离路径。最后，确定跃迁偶极矩 (TDM) 和从激发态到基态的辐射寿命。