Collect. Czech. Chem. Commun. 2011, 76, 713-742
Published online 2011-05-04 06:17:53

Parallelized implementation of the CCSD(T) method in MOLCAS using optimized virtual orbitals space and Cholesky decomposed two-electron integrals

Michal Pitoňáka,b,*, Francesco Aquilantec, Pavel Hobzab,d, Pavel Neográdya, Jozef Nogae,f and Miroslav Urbana,g

a Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská Dolina, SK-842 15 Bratislava, Slovak Republic
b Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i. and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
c Department of Physical and Analytical Chemistry, Quantum Chemistry, Uppsala University, P.O. Box 518, SE-75120 Uppsala, Sweden
d Department of Physical Chemistry, Palacký University, 771 46 Olomouc, Czech Republic
e Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, SK-842 15 Bratislava, Slovak Republic
f Institute of Inorganic Chemistry, Slovak Academy of Sciences, SK-845 36 Bratislava, Slovak Republic
g Slovak University of Technology in Bratislava, Faculty of Materials, Science and Technology in Trnava, Institute of Materials, J. Bottu 24, SK-917 24 Trnava, Slovak Republic


Parallelized implementation of the coupled cluster singles doubles with non-iterative triples in the MOLCAS program suite is described. The code benefits from the Cholesky decomposition of two-electron integrals and the algorithm is particularly designed for calculations using reduced optimized virtual orbital space. Different aspects of parallelization and its efficiency are discussed based on our recent successful calculations for medium sized molecules involving more than 1000 basis functions.

Keywords: Ab initio calculations; Electronic structure; Quantum chemistry; Coupled cluster; Cholesky decomposition; Parallelization; Noncovalent interaction; MOLCAS.

References: 55 live references.