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- Bernhardsson, Anders, et al.
(author)
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A direct implementation of the second-order derivatives of multiconfigurational SCF energies and an analysis of the preconditioning in the associated response equation
- 1999
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In: Molecular Physics. - : Informa UK Limited. - 0026-8976 .- 1362-3028. ; 96:4, s. 617-628
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Journal article (peer-reviewed)abstract
- A direct implementation of the reduced multiplication scheme of the Rys-Gauss quadrature in the computation of the second-order geometric derivatives for MCSCF wavefunctions is presented. Characteristics unique to this implementation are simultaneous evaluation of first- and second-order two-electron integral derivatives, compact representation of intermediate elements and efficient prescreening. Finally, a novel technique for the preconditioning of the response equations is reported. Applications sizing up to 510 basis functions are included in the presentation.
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