title: Assessing the accuracy of new geminal-based approaches.
abstract: We present a systematic theoretical study on the dissociation of diatomic molecules and their spectroscopic constants using our recently presented geminal-based wave function ansätze. Specifically, the performance of the antisymmetric product of rank two geminals (APr2G), the antisymmetric product of 1-reference-orbital geminals (AP1roG) and its orbital-optimized variant (OO-AP1roG) are assessed against standard quantum chemistry methods. Our study indicates that these new geminal-based approaches provide a cheap, robust, and accurate alternative for the description of bond-breaking processes in closed-shell systems requiring only mean-field-like computational cost. In particular, the spectroscopic constants obtained from OO-AP1roG are in very good agreement with reference theoretical and experimental data.
authors.affiliation: Department of Chemistry and Chemical Biology, McMaster University , 1280 Main Street West, L8S 4M1, Hamilton, Ontario, Canada.
authors.forename: Paweł
authors.initials: P
authors.lastname: Tecmer
authors.forename: Katharina
authors.initials: K
authors.lastname: Boguslawski
authors.forename: Paul A
authors.initials: PA
authors.lastname: Johnson
authors.forename: Peter A
authors.initials: PA
authors.lastname: Limacher
authors.forename: Matthew
authors.initials: M
authors.lastname: Chan
authors.forename: Toon
authors.initials: T
authors.lastname: Verstraelen
authors.forename: Paul W
authors.initials: PW
authors.lastname: Ayers