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Usvyat, Denis

Linear-scaling explicitly correlated treatment of solids: Periodic local MP2-F12 method

Usvyat, Denis (2013) Linear-scaling explicitly correlated treatment of solids: Periodic local MP2-F12 method. Journal of Chemical Physics 139, p. 194101.

Date of publication of this fulltext: 20 Oct 2016 10:56
Article
DOI to cite this document: 10.5283/epub.34734


Abstract

Theory and implementation of the periodic local MP2-F12 method in the 3*A fixed-amplitude ansatz is presented. The method is formulated in the direct space, employing local representation for the occupied, virtual, and auxiliary orbitals in the form of Wannier functions (WFs), projected atomic orbitals (PAOs), and atom-centered Gaussian-type orbitals, respectively. Local approximations are ...

Theory and implementation of the periodic local MP2-F12 method in the 3*A fixed-amplitude ansatz is presented. The method is formulated in the direct space, employing local representation for the occupied, virtual, and auxiliary orbitals in the form of Wannier functions (WFs), projected atomic orbitals (PAOs), and atom-centered Gaussian-type orbitals, respectively. Local approximations are introduced, restricting the list of the explicitly correlated pairs, as well as occupied, virtual, and auxiliary spaces in the strong orthogonality projector to the pair-specific domains on the basis of spatial proximity of respective orbitals. The 4-index two-electron integrals appearing in the formalism are approximated via the direct-space density fitting technique. In this procedure, the fitting orbital spaces are also restricted to local fit-domains surrounding the fitted densities. The formulation of the method and its implementation exploits the translational symmetry and the site-group symmetries of the WFs. Test calculations are performed on LiH crystal. The results show that the periodic LMP2-F12 method substantially accelerates basis set convergence of the total correlation energy, and even more so the correlation energy differences. The resulting energies are quite insensitive to the resolution-of-the-identity domain sizes and the quality of the auxiliary basis sets. The convergence with the orbital domain size is somewhat slower, but still acceptable. Moreover, inclusion of slightly more diffuse functions, than those usually used in the periodic calculations, improves the convergence of the LMP2-F12 correlation energy with respect to both the size of the PAO-domains and the quality of the orbital basis set. At the same time, the essentially diffuse atomic orbitals from standard molecular basis sets, commonly utilized in molecular MP2-F12 calculations, but problematic in the periodic context, are not necessary for LMP2-F12 treatment of crystals. (C) 2013 AIP Publishing LLC.



Involved Institutions


Details

Item typeArticle
Journal or Publication TitleJournal of Chemical Physics
Publisher:AMER INST PHYSICS
Place of Publication:MELVILLE
Volume:139
Page Range:p. 194101
Date2013
InstitutionsChemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Research Group Theoretical Chemistry > PD Dr. Denis Usvyat
Identification Number
ValueType
10.1063/1.4829898DOI
KeywordsCOUPLED-CLUSTER THEORY; PLESSET PERTURBATION-THEORY; COMPOSITE ENERGY-BANDS; ELECTRON CORRELATION; BASIS-SETS; MP2-R12 CALCULATIONS; WAVE-FUNCTIONS; WANNIER FUNCTIONS; CORRELATION CUSP; AB-INITIO;
Dewey Decimal Classification500 Science > 540 Chemistry & allied sciences
StatusPublished
RefereedYes, this version has been refereed
Created at the University of RegensburgYes
URN of the UB Regensburgurn:nbn:de:bvb:355-epub-347344
Item ID34734

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