Collect. Czech. Chem. Commun. 2003, 68, 357-373

The Laplace Transform Perturbative Triples Correction Ansatz

Pere Constans and Gustavo E. Scuseria*

Department of Chemistry, Rice University, Houston, TX 77005-1892, U.S.A.


We describe the implementation of the spin-unrestricted Laplace transform fourth-order perturbative triples correction. A reduction in the computational scaling with respect to canonical implementations is attained without relying on the large molecule asymptote. The intrinsic scaling difficulties that the Laplace equations exhibit upon increasing the size of the basis sets are properly addressed. The method is suited for medium-size molecules.

Keywords: Laplace factorization; Perturbative triples correction; Natural orbitals; Coupled cluster; CCSD(T); Perturbation theory; Naphthalene; Ab initio calculations.

References: 31 live references.