title: How to calculate H3 better.
abstract: Efficient optimization of the basis set is key to achieving a very high accuracy in variational calculations of molecular systems employing basis functions that are explicitly dependent on the interelectron distances. In this work we present a method for a systematic enlargement of basis sets of explicitly correlated functions based on the iterative-complement-interaction approach developed by Nakatsuji [Phys. Rev. Lett. 93, 030403 (2004)]. We illustrate the performance of the method in the variational calculations of H(3) where we use explicitly correlated Gaussian functions with shifted centers. The total variational energy (-1.674 547 421 Hartree) and the binding energy (-15.74 cm(-1)) obtained in the calculation with 1000 Gaussians are the most accurate results to date.
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA. pavanell@email.arizona.edu
authors.forename: Michele
authors.initials: M
authors.lastname: Pavanello
authors.forename: Wei-Cheng
authors.initials: WC
authors.lastname: Tung
authors.forename: Ludwik
authors.initials: L
authors.lastname: Adamowicz