It is demonstrated that the inclusion of the L1-norm of the amplitude vector in the coupled-cluster (CC) equations enables to formulate different levels of approximation of the CC model. By using L1-regularised CC theories (L1-CCD, L1-CCSD), the importance of different excited configurations is investigated. The examples of the application of the L1-regularised CC method shown include both the nonempirical and semiempirical levels of the CC theory.
- coupled-cluster theory
ASJC Scopus subject areas
- Molecular Biology
- Condensed Matter Physics
- Physical and Theoretical Chemistry