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Masur, Oliver ; Usvyat, Denis ; Schütz, Martin

Efficient and accurate treatment of weak pairs in local CCSD(T) calculations

Masur, Oliver, Usvyat, Denis und Schütz, Martin (2013) Efficient and accurate treatment of weak pairs in local CCSD(T) calculations. Journal of Chemical Physics 139, S. 164116.

Veröffentlichungsdatum dieses Volltextes: 21 Okt 2016 11:21
Artikel
DOI zum Zitieren dieses Dokuments: 10.5283/epub.34735


Zusammenfassung

Local coupled cluster theory is based on (i) a restriction of the list of pairs (or triples) of occupied molecular orbitals, and (ii) a truncation of the virtual space to orbital pair (or triple) specific subspaces. The latter is motivated by an exponential decay of the contributions to the pair energy with respect to the distance between related local occupied and virtual orbitals; the former ...

Local coupled cluster theory is based on (i) a restriction of the list of pairs (or triples) of occupied molecular orbitals, and (ii) a truncation of the virtual space to orbital pair (or triple) specific subspaces. The latter is motivated by an exponential decay of the contributions to the pair energy with respect to the distance between related local occupied and virtual orbitals; the former only by a polynomial R-6 decay with respect to the distance R between the two occupied orbitals of the pair. Consequently, the restriction of the pair list is more critical, and contributions of pairs should not be neglected unless the corresponding interorbital distance is really large. In local coupled cluster theory pairs are usually discriminated on the basis of the interorbital distance, or the size of the 2nd order Moller-Plesset perturbation theory (MP2) estimate of the pair energy. Only strong pairs are treated at the full coupled cluster level, while weak pairs are treated just at the level of MP2. Yet MP2 might be problematic in certain cases, for example, pi-stacking is badly described by MP2, etc. We propose to substitute the MP2 treatment of weak pairs by an approach based on ring-CCD by including third-order diagrams with R-6 decay behavior. Such an approach is clearly superior; it provides higher accuracy, while the computational cost is not significantly higher than that of a MP2 based treatment of weak pairs. (C) 2013 AIP Publishing LLC.



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Details

DokumentenartArtikel
Titel eines Journals oder einer ZeitschriftJournal of Chemical Physics
Verlag:AMER INST PHYSICS
Ort der Veröffentlichung:MELVILLE
Band:139
Seitenbereich:S. 164116
Datum2013
InstitutionenChemie und Pharmazie > Institut für Physikalische und Theoretische Chemie > Arbeitskreis Theoretische Chemie (Theoretical Chemistry) > Prof. Dr. Martin Schütz
Chemie und Pharmazie > Institut für Physikalische und Theoretische Chemie > Arbeitskreis Theoretische Chemie (Theoretical Chemistry) > PD Dr. Denis Usvyat
Chemie und Pharmazie > Institut für Physikalische und Theoretische Chemie > Arbeitskreis Theoretische Chemie (Theoretical Chemistry) > PD Dr. Denis Usvyat
Identifikationsnummer
WertTyp
10.1063/1.4826534DOI
Stichwörter / KeywordsPLESSET PERTURBATION-THEORY; ELECTRON CORRELATION METHODS; COUPLED-CLUSTER THEORY; DENSITY FITTING APPROXIMATIONS; TRIPLES CORRECTION T; BASIS-SETS; CONFIGURATION-INTERACTION; MOLECULAR-SYSTEMS; WAVE-FUNCTIONS; PNO-CI;
Dewey-Dezimal-Klassifikation500 Naturwissenschaften und Mathematik > 540 Chemie
StatusVeröffentlicht
BegutachtetJa, diese Version wurde begutachtet
An der Universität Regensburg entstandenJa
URN der UB Regensburgurn:nbn:de:bvb:355-epub-347350
Dokumenten-ID34735

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