TY - JOUR
T1 - Relativistic two-electron repulsion operator formulas for the Douglas–Kroll method
AU - Inoue, Nobuki
AU - Watanabe, Yoshihiro
AU - Nakano, Haruyuki
N1 - Funding Information:
This work was supported by the Japan Society for the Promotion of Science ( JSPS ) Kakenhi, Grant Numbers: JP14J06668 to NI and JP18K05036 to HN.
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/1
Y1 - 2021/1
N2 - Two-electron repulsion operator formulas for the second- and third-order Douglas–Kroll (DK2 and DK3) method were derived and implemented. The formulas were applied to helium-like ions with Z = 10, 20, …, 130, and to rare gas atoms. The energies obtained for the DK2 and DK3 two-electron operators showed differences from the four-component method that were one order of magnitude smaller than those of the nonrelativistic and DK1 two-electron operators. Approximation formulas for the small component-type two-electron integrals were also derived; they were applied to the helium-like ions with Z = 80 and 130 and were numerically confirmed to reproduce unapproximated values very accurately.
AB - Two-electron repulsion operator formulas for the second- and third-order Douglas–Kroll (DK2 and DK3) method were derived and implemented. The formulas were applied to helium-like ions with Z = 10, 20, …, 130, and to rare gas atoms. The energies obtained for the DK2 and DK3 two-electron operators showed differences from the four-component method that were one order of magnitude smaller than those of the nonrelativistic and DK1 two-electron operators. Approximation formulas for the small component-type two-electron integrals were also derived; they were applied to the helium-like ions with Z = 80 and 130 and were numerically confirmed to reproduce unapproximated values very accurately.
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U2 - 10.1016/j.cplett.2020.138158
DO - 10.1016/j.cplett.2020.138158
M3 - Article
AN - SCOPUS:85096179247
SN - 0009-2614
VL - 762
JO - Chemical Physics Letters
JF - Chemical Physics Letters
M1 - 138158
ER -