When Gold Is Not Enough: Platinum Standard of Quantum Chemistry with N⁷ Cost.

ABSTRACT: In this paper, we extend the rank-reduced coupled-cluster formalism to the calculation of non-iterative energy corrections due to quadruple excitations. There are two major components of the proposed formalism. The first is an approximate compression of the quadruple excitation amplitudes using the Tucker format. The second is a modified functional used for the evaluation of the corrections which gives exactly the same results for the exact amplitudes, but is less susceptible to errors resulting from the aforementioned compression. We show, both theoretically and numerically, that the computational cost of the proposed method scales as the seventh power of the system size. Using reference results for a set of small molecules, the method is calibrated to deliver relative accuracy of a few p

SUBMITTER: Lesiuk M 

PROVIDER: S-EPMC9648181 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature