Bross David H, Parmar Payal, Peterson Kirk A
Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, USA.
J Chem Phys. 2015 Nov 14;143(18):184308. doi: 10.1063/1.4935375.
The first 6 ionization potentials (IPs) of the uranium atom have been calculated using multireference configuration interaction (MRCI+Q) with extrapolations to the complete basis set limit using new all-electron correlation consistent basis sets. The latter was carried out with the third-order Douglas-Kroll-Hess Hamiltonian. Correlation down through the 5s5p5d electrons has been taken into account, as well as contributions to the IPs due to the Lamb shift. Spin-orbit coupling contributions calculated at the 4-component Kramers restricted configuration interaction level, as well as the Gaunt term computed at the Dirac-Hartree-Fock level, were added to the best scalar relativistic results. The final ionization potentials are expected to be accurate to at least 5 kcal/mol (0.2 eV) and thus more reliable than the current experimental values of IP3 through IP6.
利用多参考组态相互作用（MRCI+Q）方法，并使用新的全电子相关一致基组外推至完备基组极限，计算了铀原子的前6个电离势（IP）。后者采用三阶道格拉斯-克罗尔-赫斯哈密顿量进行。考虑了5s5p5d电子以下的相关效应，以及由于兰姆位移对电离势的贡献。在四分量克莱默斯受限组态相互作用水平计算的自旋-轨道耦合贡献，以及在狄拉克-哈特里-福克水平计算的冈特项，被添加到最佳标量相对论结果中。最终的电离势预计至少精确到5千卡/摩尔（0.2电子伏特），因此比目前IP3到IP6的实验值更可靠。
