Explicitly-correlated coupled cluster method for long-range dispersion coefficients

[Display omitted] •The CCSD(F12)-based method is implemented for treatment of C6 dispersion coefficients.•Highly accurate C6 coefficients are obtained for the set of molecules.•The method is based on Casimir-Polder equation for dispersion coefficients. A method of calculation of long-range dispersio...

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Bibliographic Details
Published in:Chemical physics letters 2017-03, Vol.672, p.133-136
Main Authors: Bokhan, Denis, Trubnikov, Dmitrii N., Perera, Ajith, Bartlett, Rodney J.
Format: Article
Language:English
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Summary:[Display omitted] •The CCSD(F12)-based method is implemented for treatment of C6 dispersion coefficients.•Highly accurate C6 coefficients are obtained for the set of molecules.•The method is based on Casimir-Polder equation for dispersion coefficients. A method of calculation of long-range dispersion C6 coefficients with wavefunctions, corresponding to linearly approximated explicitly correlated coupled-cluster singles and doubles [CCSD(F12)] model, has been developed. Designed approach uses CCSD(F12) wave functions for the calculation of dynamic polarizabilities at complex frequencies with further utilization of Casimir-Polder formula. As a part of the algorithm, the explicitly-correlated version of the coupled-perturbed CCSD equations for the case of complex frequencies has also been implemented. Numerical tests, conducted for the set of molecules show good agreement between dispersion coefficients, calculated with developed explicitly-correlated method and corresponding complete basis set results in regular CCSD already at triple-ζ level.
ISSN:0009-2614
1873-4448
DOI:10.1016/j.cplett.2017.01.049