Pototschnig Johann V, Krois Günter, Lackner Florian, Ernst Wolfgang E
Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
J Chem Phys. 2014 Dec 21;141(23):234309. doi: 10.1063/1.4903791.
Excited states and the ground state of the diatomic molecule RbSr were calculated by post Hartree-Fock molecular orbital theory up to 22 000 cm(-1). We applied a multireference configuration interaction calculation based on multiconfigurational self-consistent field wave functions. Both methods made use of effective core potentials and core polarization potentials. Potential energy curves, transition dipole moments, and permanent electric dipole moments were determined for RbSr and could be compared with other recent calculations. We found a good agreement with experimental spectra, which have been obtained recently by helium nanodroplet isolation spectroscopy. For the lowest two asymptotes (Rb (5s (2)S) + Sr (5s4d (3)P°) and Rb (5p (2)P°) + Sr (5s(2) (1)S)), which exhibit a significant spin-orbit coupling, we included relativistic effects by two approaches, one applying the Breit-Pauli Hamiltonian to the multireference configuration interaction wave functions, the other combining a spin-orbit Hamiltonian and multireference configuration interaction potential energy curves. Using the results for the relativistic potential energy curves that correspond to the Rb (5s (2)S) + Sr (5s4d (3)P°) asymptote, we have simulated dispersed fluorescence spectra as they were recently measured in our lab. The comparison with experimental data allows to benchmark both methods and demonstrate that spin-orbit coupling has to be included for the lowest states of RbSr.
利用后哈特里-福克分子轨道理论计算了双原子分子RbSr的激发态和基态，计算范围高达22000厘米-1。我们基于多组态自洽场波函数应用了多参考组态相互作用计算。两种方法都使用了有效核势和核极化势。确定了RbSr的势能曲线、跃迁偶极矩和永久电偶极矩，并可与其他近期计算结果进行比较。我们发现与最近通过氦纳米滴隔离光谱获得的实验光谱吻合良好。对于最低的两个渐近线（Rb(5s 2S)+Sr(5s4d 3P°)和Rb(5p 2P°)+Sr(5s2 1S)），它们表现出显著的自旋-轨道耦合，我们通过两种方法纳入了相对论效应，一种是将 Breit-Pauli哈密顿量应用于多参考组态相互作用波函数，另一种是将自旋-轨道哈密顿量与多参考组态相互作用势能曲线相结合。利用对应于Rb(5s 2S)+Sr(5s4d 3P°)渐近线的相对论势能曲线结果，我们模拟了最近在我们实验室测量的色散荧光光谱。与实验数据的比较可以对两种方法进行基准测试，并证明对于RbSr的最低态必须考虑自旋-轨道耦合。
