Basis-set convergence of the two-electron Darwin term

被引:32
作者
Halkier, A
Helgaker, T
Klopper, W
Olsen, J
机构
[1] Univ Utrecht, Debye Inst, Theoret Chem Grp, NL-3508 TB Utrecht, Netherlands
[2] Univ Cambridge, Dept Chem, Cambridge CB2 1EW, England
[3] Aarhus Univ, Dept Chem, DK-8000 Aarhus, Denmark
[4] Univ Oslo, Dept Chem, N-0315 Oslo, Norway
关键词
D O I
10.1016/S0009-2614(00)00161-5
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The basis-set convergence of the correlation contribution to the two-electron Darwin term with the cardinal number(X) of the basis set in conventional calculations is investigated for He, H-2, Ne, and HF. For He, the form D-corr(2e)(X) = D-0(2e) + C1X-1 describes the convergence for numerically optimized basis sets of the principal-expansion type accurately, and, for the larger of these basis sets, two-point extrapolated values obtained with this X-1 form are within 0.1% of the basis-set limit established with the Hylleraas expansion. For all four systems, the X-1 form describes the convergence of the correlation-consistent cc-pVXZ basis sets accurately. Accordingly, for these basis sets, two-point X-1-extrapolated values represent significant improvements on the unextrapolated results. (C) 2000 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:287 / 295
页数:9
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