Oscillator Strengths in the Framework of Equation of Motion Multilevel CC3.

ABSTRACT: We present an efficient implementation of the equation of motion oscillator strengths for the closed-shell multilevel coupled cluster singles and doubles with perturbative triples method (MLCC3) in the electronic structure program e^T. The orbital space is split into an active part treated with CC3 and an inactive part computed at the coupled cluster singles and doubles (CCSD) level of theory. Asymptotically, the CC3 contribution scales as O(nVnv3no3) floating-point operations, where n_V is the total number of virtual orbitals while n_v and n_o are the number of active virtual and occupied orbitals, respectively. The CC3 contribution, thus, only scales linearly with the full system size and can become negligible com

SUBMITTER: Paul AC 

PROVIDER: S-EPMC9476665 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature