icMRCI+Q理论研究CF离子12个-S态和23个?态的光谱性质

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-ccpV5Z和aug-cc-pV6Z计算了CF~+离子第一离解极限C~+(~2p_u)+F(~2P_u)对应的12个∧-S态(X~l∑~+,a~3∏,1~3∑~+,1~3Δ,1~1∑~-,1~1∑~-,1~3∑~-,2~1∑~+,1~1∏,2~3∏,2~1∏和2~3∑~+)所产生的23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9个∧-S态和16个Ω态的光谱常数,并且X~1∑~+,a~3∏~(势阱一)∧-S态的光谱常数与已有的实验结果非常符合.此外,计算了CF自由基X~2∏态到CF~+离子束缚和准束缚的9个∧-S态的垂直电离势和绝热电离势,并且CF~+(X~1∑~+)←CF(X~2∏)和CF~+(a~3∏(势阱一))←CF(X~2∏)的垂直电离势和绝热电离势与相应的实验结果也非常符合.由a~3∏,1~1∏态和其他激发∧-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a~3∏~(势阱一),1~1∏~(势阱一)和2~1∑~+态的预解离机理.计算的23个Ω态离解极限处的相对能量与实验结果十分吻合.最后计算了(2)0+~(势阱一)(v'=0-5),(1)1~(势阱一)(v'=0-5)和(2)1~(势阱一)(v'=0)到X0~+态跃迁的Franck-Condon因子和辐射寿命.

icMRCI+Q study on spectroscopic properties of twelve Λ-S states and twenty-three Ω states of the CF+ cation

The potential energy curves of twenty-three Ω states generated from the twelve Λ-S states (X¹Σ⁺, a³Π, 1³Σ⁺, 1³Δ, 1¹Δ, 1¹Σ^-, 1³Σ^-, 2¹Σ⁺, 1¹Π, 2³Π, 2¹Π and 2³Σ⁺) correlating with the first dissociation channel C⁺(²P_u)+ F(²P_u) of the CF⁺ cation are obtained by using the internally contracted multireference configuration interaction approach with the Davidson modification (icMRCI+Q) on the basis of the correlation-consistent aug-cc-pV5Z and aug-cc-pV6Z basis sets for the first time. 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 nine Λ-S and sixteen Ω states of the CF⁺ cation are obtained. And the spectroscopic parameters of X¹Σ⁺and a³Π^{1st well}Λ-S states which are in very good agreement with experimental results are achieved. Furthermore, the vertical and adiabatic ionization potentials of ionization from the X²Π state of CF radical to the bound and quasibound nine Λ-S states of the CF⁺ cation are calculated, and the vertical and adiabatic ionization potentials of the CF⁺(X¹Σ⁺) ← CF(X²Π ) and CF⁺(a³Π^{1st well}) ← CF(X²Π ) ionizations are also in good agreement with the corresponding experimental values. Various curve crossings of Λ -S states are revealed, and with the help of our computed spin-orbit coupling matrix elements, the predissociation mechanisms of the a³Π^{1st well}, 1¹Π^{1st well} and 2¹Σ⁺ states are analyzed for the first time. The spin-orbit-induced predissociations for the a³Π^{1st well}, 1¹Π^{1st well} and 2¹Σ⁺Λ-S states could happen, and the predissociations of the a³Π^{1st well}, 1¹Π^{1st well} and 2¹Σ ⁺Λ-S states start around the vibrational levels ν' = 15, ν' = 1 and ν' = 1, respectively. Relative energies of the twenty-three Ω states in the dissociation limits are given, and our calculations match the experimental results very well. Finally, the Franck-Condon factors and radiative lifetimes of transitions from (2) 0^{+1st well} (ν;'=0–5), (1) 1^{1st well} (ν'=0–5) and (2) 1^{1st well} (ν'=0) to X0⁺Ω states are predicted for the future laboratory research.