Highly correlated calculations using optimized virtual orbital space with controlled accuracy. Application to counterpoise corrected interaction energy calculations

0380016 - ÚOCHB 2013 RIV US eng J - Journal Article
Kraus, M. - Pitoňák, Michal - Hobza, Pavel - Urban, M. - Neogrady, P.
Highly correlated calculations using optimized virtual orbital space with controlled accuracy. Application to counterpoise corrected interaction energy calculations.
International Journal of Quantum Chemistry. Roč. 112, č. 4 (2012), s. 948-959. ISSN 0020-7608. E-ISSN 1097-461X
R&D Projects: GA MŠMT LC512
Grant - others:Slovak Research and Development Agency(SK) APVV-20-018405; Slovak Grant Agency VEGA(SK) 1/0428/09; Slovak Grant Agency VEGA(SK) 1/0520/10
Institutional research plan: CEZ:AV0Z40550506
Keywords : OVOS * FNO * nocovalent interactions * hydrogen bonding * ctacking
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 1.306, year: 2012

In this work, we investigate the correlation between error introduced by truncation of optimized virtual orbital space (OVOS) on the MP2 level (YMP2) with the error of the post-MP2 contributions, such as the CCSD-MP2 (i.e., gamma deltaCCSD), CCSD(T)-MP2 (i.e., gamma deltaCCSD(T)), or the (T) separately. We found a correlation between the YMP2 and several other quantities, such as the percent of recovered optimization functional value in the truncated OVOS (OF%), or the aforementioned gamma deltaCCSD, gamma deltaCCSD(T), Y(T), which is to good approximation linear in the logarithmic scale. These correlations open a possibility to control the accuracy of the post-MP2 calculations in the truncated OVOS, because the YMP2 and the OF% are easily obtained, almost as a byproduct of the virtual orbital optimization. According to the results present in this work, knowledge of the YMP2 or the OF% allows us to safely estimate the order of magnitude of the error of the post-MP2 corrections. To keep the accuracy of, for instance, CCSD(T) correlation energy calculated in the truncated OVOS within 1.10-5 - 1.10-6 Hartree error bars, we can typically reduce only a few percent of the OVOS, although this value increases slightly with enlarging the atomic orbital (AO) basis set and the number of inactive occupied orbitals. Still, even such a modest reduction can save more then a half of the computation time, compared with calculations in the full VOS. The situation is, however, much more favourable in case of counterpoise (CP) corrected calculations of interaction energy, where this methodology enables safe truncation of significant part of OVOS of monomers, resulting from the presence of the ghost AO. Dimension of such truncated OVOS essentially corresponds to CP-uncorrected calculations, thus leads to more than an order of magnitude speedup of calculation of monomers.
Permanent Link: http://hdl.handle.net/11104/0210846