Perturbative approximations to single and double spin flip equation of motion coupled cluster singles doubles methods
Title | Perturbative approximations to single and double spin flip equation of motion coupled cluster singles doubles methods |
Publication Type | Journal Article |
Year of Publication | 2013 |
Authors | Dutta, AKumar, Pal, S, Ghosh, D |
Journal | Journal of Chemical Physics |
Volume | 139 |
Issue | 12 |
Pagination | 124116 |
Date Published | SEP |
ISSN | 0021-9606 |
Abstract | Spin flip equation of motion coupled cluster (EOM-SF-CC) can correctly treat situations involving electronic degeneracies or near degeneracies, e. g., bond breaking, di- and tri-radicals, etc. However, for large systems EOM-SF-CC (even in single and double excitations) is computationally prohibitively expensive. Therefore, earlier approximations to EOM-SF-CC methods such as spin flip configuration interaction singles with perturbative doubles (SF-CIS(D)) have been proposed. In this work, we present a new perturbative approximation to EOM-SF-CC, which has been found to be more accurate than SF-CIS(D). The capabilities, advantages, and timings of the new approach have been demonstrated considering the singlet-triplet gaps in di- and triradicals as well as bond breaking examples. The method is extended to double spin flip EOM-CC and its capabilities have been tested. (C) 2013 AIP Publishing LLC. |
DOI | 10.1063/1.4821936 |
Type of Journal (Indian or Foreign) | Foreign |
Impact Factor (IF) | 3.122 |