Abstract
In this short paper a new version of the multireference (MR) averaged coupled pair functional (ACPF) and the MR averaged quadratic coupled-cluster (AQCC) methods is presented which corrects the failure of the original formulation in case of close-lying states described with small reference space. This new version is based on a functional which also includes the reference energy, i.e. instead of optimizing the correlation energy, the total energy will be made stationary with respect the wave function parameters. It is demonstrated that this method gives smooth potential energy surfaces in case of avoided crossings.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: 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.