Alekseyev Aleksey B, Liebermann Heinz-Peter, Buenker Robert J
Fachbereich C-Theoretische Chemie, Bergische Universität Wuppertal, Germany.
Phys Chem Chem Phys. 2007 Oct 7;9(37):5088-95. doi: 10.1039/b706670h. Epub 2007 Jul 24.
The multireference Spin-Orbit (SO) Configuration Interaction (CI) method in its Lambda-S Contracted SO-CI (LSC-SO-CI) version is employed to calculate potential energy curves for the ground and low-lying excited states of the ArH(+) cation. For the first time, electric dipole moments are also computed in the approach, including SO coupling for transitions to the states responsible for the first absorption continuum (A-band) of ArH(+). On this basis, the partial and total absorption spectra in this energy range are obtained. It is shown that absorption in the A-band is dominated by the parallel A(1)Sigma(+)<--X(1)Sigma(+) transition. In the low-energy part of the band (<95 x 10(3) cm(-1)) the absorption is caused by the perpendicular B(1)Pi<--X(1)Sigma(+) excitation, but transitions to the b(3)Pi(0(+),1) states are also not negligible. The branching ratio Gamma for the final photodissociation products is calculated and it is shown to increase smoothly from 0 in the red tail of the band to 1 at E>or= 10(5) cm(-1). The latter value corresponds to the exclusive formation of the spin-excited Ar(+)((2)P(1/2)) ions, and thus leads to the inverse population of the Ar(+)((2)P(1/2)-(2)P(3/2)) ion states.
采用多参考自旋轨道（SO）组态相互作用（CI）方法的Lambda-S收缩SO-CI（LSC-SO-CI）版本，来计算ArH(+)阳离子基态和低激发态的势能曲线。首次在该方法中计算了电偶极矩，包括向负责ArH(+)第一吸收连续谱（A带）的态跃迁的SO耦合。在此基础上，得到了该能量范围内的部分吸收光谱和总吸收光谱。结果表明，A带中的吸收主要由平行的A(1)Σ(+)←X(1)Σ(+)跃迁主导。在该能带的低能量部分（<95×10³cm⁻¹），吸收是由垂直的B(1)Π←X(1)Σ(+)激发引起的，但向b(3)Π(0(+),1)态的跃迁也不可忽略。计算了最终光解离产物的分支比Γ，结果表明它从能带红端的0平滑增加到E≥10⁵cm⁻¹时的1。后一个值对应于自旋激发的Ar(+)((2)P(1/2))离子的唯一形成，从而导致Ar(+)((2)P(1/2)-(2)P(3/2))离子态的反转分布。
