The electronic structures of silicon monobromide (SiBr) correlating with the lowest three dissociation channels are studied using high-level configuration interaction method. The spin-orbit coupling (SOC) effect and core-valence (CV) correlations effect are taken into account to improve the accuracy of electronic structures. Based on the calculated electronic structures of the lowest three dissociation channels of SiBr, the spectroscopic constants of quasibound and bound electronic states are fitted, which are coincided with the results of experiment. The dipole moment curves (DMs) of the lowest three dissociation channels of SiBr are obtained, and the abrupt change of DMs nearby the avoided crossing point are explained by the variation of electronic configurations of the corresponding states. With the help of the calculated SOC matrix elements, the predissociation channels of the low-lying vibrational states of 2Δ(Ⅱ) and 2Π(Ⅲ) sates are analyzed. The complicated interaction between crossing states is investigated. The ν'≥0 vibrational states of 2Δ(Ⅱ) and ν′≥2 vibrational states of 2Π(Ⅲ) would predissociate rapidly through predissociation channels of 2Δ(Ⅱ)-2Π(Ⅱ) and 2Π(Ⅲ)-2Σ+(Ⅱ). Finally, the transition properties of A2Σ+-X2Π, 2∆(Ⅱ)-X2Π, 2Σ+(Ⅱ)-X2Π, 2Π(Ⅲ)-X2Π, 1/2(Ⅱ)-X2Π1/2, 1/2(Ⅲ)-X2Π1/2 and 3/2(Ⅱ)-X2Π1/2 transitions are investigated, and radiative lifetime of bound states are evaluated.

中文翻译：

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MRCI+Q 计算一溴化硅的电子结构和低位电子态的光谱，包括自旋轨道耦合效应


采用高级构型交互方法研究了与最低三个解离通道相关的一溴化硅 （SiBr） 的电子结构。考虑了自旋轨道耦合 （SOC） 效应和核价 （CV） 相关性效应，以提高电子结构的准确性。基于计算出 SiBr 最低三个解离通道的电子结构，拟合了准束缚电子态和束缚电子态的光谱常数，这与实验结果一致。得到了 SiBr 最低三个解离通道的偶极矩曲线 （DMs），并通过相应状态的电子构型的变化来解释避开交叉点附近 DMs 的突变。借助计算的 SOC 基体单元，分析了 2Δ（II.） 和 2Π（III.） 状态的低洼振动状态的预解离通道。研究了跨状态之间的复杂交互。2Δ（II.） 的 ν'≥0 振动态和 2Π（III.） 的 ν′≥2 振动态会通过 2Δ（II.）-2Π（II.） 和 2Π（III.）-2Σ+（II.） 的预解离通道迅速预解离。最后，研究了 A2Σ+-X2Π、2∆（II.）-X2Π、2Σ+（II.）-X2Π、2Π（III.）-X2Π、1/2（II.）-X2Π1/2、1/2（III.）-X2Π1/2 和 3/2（II.）-X2Π1/2 跃迁的跃迁特性，并评估了束缚态的辐射寿命。