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中国物理学会期刊

一氟化碳电子态的光谱性质和预解离机理的理论研究

CSTR: 32037.14.aps.64.153101

Theoretical study on spectroscopic properties and predissociation mechanisms of the electronic states of carbon monofluoride

CSTR: 32037.14.aps.64.153101
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  • 采用考虑Davidson修正的内收缩多参考组态相互作用(icMRCI+Q)方法结合相关一致基组aug-cc-pV5Z和aug-cc-pV6Z首次计算了一氟化碳(CF)11个Λ-S 态(X2Π , a4Σ-, A2Σ+, B2Δ, 14Π, 12Σ-, 24Π, 14Δ , 14Σ+, 22Σ-和24Σ-) 所产生的25个Ω 态的势能曲线. 计算中考虑了旋轨耦合效应、核价相关和标量相对论修正以及将参考能和相关能分别外推至完全基组极限. 基于得到的势能曲线, 获得了束缚和准束缚的Λ-S态和Ω 态的光谱常数, 与已有的实验结果非常符合. 分析了束缚和准束缚的Λ-S态在各自平衡核间距Re处的主要电子组态. 由于14Π 和24Π态的避免交叉, 发现准束缚态24Π. 由Λ-S态势能曲线的交叉现象, 借助于计算的旋轨耦合矩阵元, 分析了a4Σ-和B2Δ 态的预解离机理. 计算了25个Ω 态的离解关系, 给出了它们的离解极限. 最后研究了A2Σ+-X2Π 跃迁特性, 本文计算得到的A2Σ+-X2Π跃迁的Frank-Condon 因子和辐射寿命与已有实验值也符合得非常好.

     

    The potential energy curves of twenty-five Ω states generated from the eleven Λ-S states (X2Π, a4Σ-, A2Σ+, B2Δ, 14Π, 12Σ-, 24Π, 14Δ, 14Σ+, 22Σ- and 24Σ-) of the carbon monofluoride are calculated using the internally contracted multireference configuration interaction approach with the Davidson modification (icMRCI+Q) in the correlation-consistent aug-cc-pV5Z and aug-cc-pV6Z basis sets, for the first time so far as we know. The spin-orbit coupling, core-valence correlation, and relativistic corrections are taken into account, and all the potential energy curves are extrapolated to the complete basis set limit by separately extrapolating the Hartree-Fock and correlation energies scheme. Based on the calculated potential energy curves, the spectroscopic parameters of the bound and quasibound Λ-S and Ω states are obtained, and a very good agreement with experiment is achieved. It demonstrates that the spectroscopic parameters of A2Σ+(1st well), 24Π Λ-S and the eleven Ω states reported here for the first time can be expected to be reliably predicted results. The 24Π quasibound state caused by avoiding crossings are found, and the important electronic configurations of the bound and quasibound Λ-S states near the equilibrium positions Re are given. Various crossings in curves of Λ-S states are revealed, and with the help of our computed spin-orbit coupling matrix elements, the predissociation mechanisms of the a4Σ- and B2Δ states are analyzed. Dissociation relationships and dissociation channels of the twenty-five Ω states also are given. The transition properties of the A2Σ+-X2Π transitions are finally predicted, and our computed Franck-Condon factors and radiative lifetimes match the available experimental results very well.

     

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