Evangelista FA, Simmonett AC, Schaefer HF, Mukherjee D, Allen WD. A companion perturbation theory for state-specific multireference coupled cluster methods.
Phys Chem Chem Phys 2009;
11:4728-41. [PMID:
19492126 DOI:
10.1039/b822910d]
[Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A partitioning scheme is applied to the state-specific Mukherjee multireference coupled cluster method to derive a companion perturbation theory (Mk-MRPT2). A production-level implementation of Mk-MRPT2 is reported. The effectiveness of the Mk-MRPT2 method is demonstrated by application to the classic F(2) dissociation problem and the lowest-lying electronic states of meta-benzyne, including computations with up to 766 atomic orbitals. We show that Mk-MRPT2 theory is particularly useful in multireference focal point extrapolations to determine ab initio limits.
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