Pushing configuration-interaction to the limit: Towards massively parallel MCSCF calculations

A new large-scale parallel multiconfigurational self-consistent field (MCSCF) implementation in the open-source NWChem computational chemistry code is presented. The generalized active space approach is used to partition large configuration interaction (CI) vectors and generate a sufficient number o...

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Bibliographic Details
Published in:The Journal of chemical physics 2017-11, Vol.147 (18), p.184111-184111
Main Authors: Vogiatzis, Konstantinos D., Ma, Dongxia, Olsen, Jeppe, Gagliardi, Laura, de Jong, Wibe A.
Format: Article
Language:English
Subjects:
Chromium
Computational chemistry
Configuration interaction
Electrons
INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Iterative methods
Mathematical analysis
Orbitals
Organic chemistry
Physics
Trimers
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Summary:A new large-scale parallel multiconfigurational self-consistent field (MCSCF) implementation in the open-source NWChem computational chemistry code is presented. The generalized active space approach is used to partition large configuration interaction (CI) vectors and generate a sufficient number of batches that can be distributed to the available cores. Massively parallel CI calculations with large active spaces can be performed. The new parallel MCSCF implementation is tested for the chromium trimer and for an active space of 20 electrons in 20 orbitals, which can now routinely be performed. Unprecedented CI calculations with an active space of 22 electrons in 22 orbitals for the pentacene systems were performed and a single CI iteration calculation with an active space of 24 electrons in 24 orbitals for the chromium tetramer was possible. The chromium tetramer corresponds to a CI expansion of one trillion Slater determinants (914 058 513 424) and is the largest conventional CI calculation attempted up to date.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.4989858