Abstract
Several coupled-cluster approximations to the full CCSDTQ model, correct through sixth order, are presented and illustrated by numerical comparions to full CI. Both iterative and non-iterative methods built upon underlying CCSDT solutions are considered. Unlike CCSDTQ, which is an ∼ n 10 computational procedure, the computational dependence of all approximations is no worse than ∼ n 9. The latter follows use of the 2 n rule of perturbation theory. The average errors compared to full CI for different methods are 0.1 to 0.3 mhartree, compared to 0.05 mhartree for CCSDTQ.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
