title: Extension of accompanying coordinate expansion and recurrence relation method for general-contraction basis sets.
abstract: An algorithm of the accompanying coordinate expansion and recurrence relation (ACE-RR), which is used for the rapid evaluation of the electron repulsion integral (ERI), has been extended to the general-contraction (GC) scheme. The present algorithm, denoted by GC-ACE-RR, is designed for molecular calculations including heavy elements, whose orbitals consist of many primitive functions with and without higher angular momentum such as d- and f-orbitals. The performance of GC-ACE-RR was assessed for (ss|ss)-, (pp|pp)-, (dd|dd)-, and (ff|ff)-type ERIs in terms of contraction length and the number of GC orbitals. The present algorithm was found to reduce the central processing unit time compared with the ACE-RR algorithm, especially for higher angular momentum and highly contracted orbitals. Compared with HONDOPLUS and GAMESS program packages, GC-ACE-RR computations for ERIs of three-dimensional gold clusters Aun (n = 1, 2, …, 10, 15, 20, and 25) are more than 10 times faster.
authors.affiliation: Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, Tokyo, 169-8555, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Hayami
authors.forename: Junji
authors.initials: J
authors.lastname: Seino
authors.forename: Hiromi
authors.initials: H
authors.lastname: Nakai
keywords: Molecular integral; accompanying coordinate expansion and recurrence relation method; electron repulsion integral; general-contraction; high angular momentum