The ab initio model potential method: Lanthanide and actinide elements

Abstract

In this paper we present relativistic core ab initio model potentials based on atomic Cowan-Griffin calculations, together with Wood-Boring spin-orbit operators and optimized Gaussian valence basis sets, for the lanthanide elements Ce to Lu and for the actinide elements Th to Lr. This completes the chemically relevant part of the Periodic Table. A ͓Kr,4d͔ core was chosen for Ce-Lu and a ͓Xe,4f ,5d͔ core was chosen for Th-Lr. Minimal (14s10p9d8 f )/͓2s1 p1d1 f ͔ and (14s10p11d9 f )/͓2s1 p1d1 f ͔ valence basis sets were, respectively, optimized for Ce-Lu and Th-Lr, and a ͓6s5 p5d4 f ͔ contraction is recommended for all these 28 elements in molecular calculations. The atomic and molecular results show the same good quality already observed for the main-group elements and the transition metal elements.

Large spin relaxation rates in trapped submerged-shell atoms

“…These large rates imply an additional spin relaxation mechanism other than spin exchange, dipolar relaxation, and second-order spin-orbit coupling, which are well known from studies with alkali metal atoms. The electrostatic quadrupole-quadrupole interaction is a long-range mechanism for driving inelastic processes in L = 0 atoms, such as seen in metastable alkaline earth metal systems [11], however, the anisotropic charge distribution in submerged-shell atoms is confined tightly near the nucleus [12]. Thus while the quadrupole-quadrupole interaction is not expected to be shielded, the interaction strength should be far weaker than in outer-shell systems.…”

Structure and spectroscopy of Pa4+ defects in Cs2ZrCl6. An ab initio theoretical study

“…27 For Pa, we observed that whereas the 5 f orbitals of neutral Pa 5 f 3 6d 1 7s 1 Ϫ 6 L obtained in Ref. 18 sis set with respect to that in Ref. 18.…”

“…26 B. The "PaCl 6 … 2À defect cluster Relativistic Cowan-Griffin-Wood-Boring 16,17 -based core AIMPs were used for both Pa ͓͑Xe, 4 f , 5d͔ core͒ 18 and Cl ͓͑Ne͔ core͒. 27 For Pa, we observed that whereas the 5 f orbitals of neutral Pa 5 f 3 6d 1 7s 1 Ϫ 6 L obtained in Ref.…”

“…18 sis set with respect to that in Ref. 18. 28 With the new d basis set and 6d spin-orbit operator, the atomic 6d spin-orbit coupling constant, 6d ϭ͗6d͉V 6d SO ͉6d͘, is 3042 cm Ϫ1 , identical to the Cowan-Griffin-Wood-Boring numerical one, and significantly larger than that of neutral Pa(5 f 3 6d 1 7s 1 Ϫ 6 L), 1199 cm Ϫ1 .…”

“…Recently, the relativistic core ab initio model potentials of the lanthanide and actinide elements based on Cowan-Griffin-Wood-Boring 16,17 atomic calculations have been published and their good performance in scalar relativistic effects has been pointed out. 18 Whereas the quality of the spin-orbit operators is good for the lanthanides, 19 it has not yet been tested for the actinide elements.…”