Multireference Mukherjee's coupled cluster method with triexcitations in the linked formulation: Efficient implementation and applications

0356822 - ÚFCH JH 2011 RIV US eng J - Journal Article
Bhaskaran-Nair, Kiran - Demel, Ondřej - Pittner, Jiří
Multireference Mukherjee's coupled cluster method with triexcitations in the linked formulation: Efficient implementation and applications.
Journal of Chemical Physics. Roč. 132, č. 15 (2010), s. 154105. ISSN 0021-9606. E-ISSN 1089-7690
R&D Projects: GA ČR GA203/07/0070
Institutional research plan: CEZ:AV0Z40400503
Keywords : clusters * Mukherjee´s coupled cluster * quantum chemistry
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 2.920, year: 2010

We have formulated the multireference Mukherjee's coupled clusters method with triexcitations (MR MkCCSDT) in the linked version and implemented it in the ACES II program package. The assessment of the new method has been performed on the first three electronic states of the oxygen molecule, on studies of singlet-triplet gap in methylene and twisted ethylene, where a comparison with other multireference CC treatments and with experimental data is available. The MR MkCCSDT results show accuracy comparable to which can be achieved with CCSDT in single reference cases. Comparison of the previously developed MkCCSD(T) method with MkCCSDT as a reference suggests, that MkCCSD(T) might be a promising candidate for an accurate treatment of systems where the static correlation plays an important role, at least for situations where small model spaces are sufficient.
Permanent Link: http://hdl.handle.net/11104/0195246