Transition energies of lanthanum, actinium, and eka-actinium (element 121)
Transition energies of lanthanum, actinium, and eka-actinium (element 121)
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DOI：
10.1063/1.476995
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发表时间：
1998-09
影响因子：
4.4
通讯作者：
E. Eliav;Sergei Shmulyian;U. Kaldor;Y. Ishikawa
中科院分区：
文献类型：
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作者：
E. Eliav;Sergei Shmulyian;U. Kaldor;Y. Ishikawa
应用相对论耦合团簇方法计算了镧、锕和类锕（121号元素）在几种电离态下的跃迁能（电离势、激发能、电子亲合能）。与现有的实验数据得到很好的协议。大的相对论效应，观察到所有三个原子，与过渡能量变化高达2.5 eV，即使是相对轻的La。La的第一电离势从7.135 eV降低到5.582 eV（实验值为5.577 eV）。在Ac中，7s壳层在6d之前被占据，分别产生Ac 2+和Ac+的7s和7s 2基态，而不是La离子的5d和5d2态。E121的基态是8 s28 p，与较轻的3族元素的ns 2（n−1）d组态比较。Breit效应对跃迁能量的影响对于包括f轨道的态是显著的（0.06- 0.1eV），而对于其它的态是很小的（低于0.02eV）。虚i轨道（l=6）的贡献也类似。
The relativistic coupled cluster method is applied to the transition energies (ionization potentials, excitation energies, electron affinities) of lanthanum, actinium, and eka-actinium (element 121) in several ionization states. Good agreement with available experimental data is obtained. Large relativistic effects are observed for all three atoms, with transition energies changing by up to 2.5 eV even for the relatively light La. The first ionization potential of La is reduced from 7.135 to 5.582 eV (the experimental value is 5.577 eV). In Ac, the 7s shell is occupied before 6d, yielding 7s and 7s2 ground states for Ac2+ and Ac+, respectively, instead of the 5d and 5d2 states for the La ions. The ground state of E121 is 8s28p, to be compared with the ns2(n−1)d configurations of the lighter group-3 elements. The Breit effect on transition energies is significant (0.06–0.1 eV) for states including f orbitals and small (below 0.02 eV) for others. The contribution of virtual i orbitals (l=6) shows similar be...