Vogler, Sigurd; Ludwig, Martin; Maurer, Marina; Ochsenfeld, Christian
(2017):
Low-scaling first-order properties within second-order Moller-Plesset perturbation theory using Cholesky decomposed density matrices.
In: Journal of Chemical Physics, Vol. 147, No. 2, 24101
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Full text not available from 'Open Access LMU'.
Abstract
An efficient implementation of energy gradients and of hyperfine coupling constants in second-order Moller-Plesset perturbation theory (MP2) is presented based on our fully atomic orbital (AO)-based approach. For the latter, an unrestricted AO-based MP2 formulation is introduced. A reduction in the dependency of the computational efficiency on the size of the basis set is achieved by a Cholesky decomposition and the prefactor is reduced by the resolution-of-the-identity approximation. Significant integral contributions are selected based on distance-including integral estimates (denoted as QQR-screening) and its reliability as a fully controlled screening procedure is demonstrated. The rate-determining steps are shown via model computations to scale cubically in the computation of energy gradients and quadratically in the case of hyperfine coupling constants. Furthermore, a significant speed-up of the computational time with respect to the canonical formulation is demonstrated. Published by AIP Publishing.