Software news and updates - Basis-set completeness profiles in two dimensions

A two-electron basis-set completeness profile is proposed by analogy with the one-electron profile introduced by D. P. Chong (Can J Chem 1995, 73, 79). It is defined as Y(alpha,beta) = Sigma(m) Sigma(n)<G(alpha)(1)G(beta)(2)\(1/r(12))\Psi(m)(1)Psi(n)(2)><Psi(m)(1)Psi(n)(2)\r(12)\G(alpha)(1)G(beta)(2)> and motivated by the expression for the basis-set truncation correction that occurs in the framework of explicitly correlated methods (G(alpha) is a scanning Gaussian-type orbital of exponent alpha and {Psi(m)} is the orthonormalized one-electron basis under study). The two-electron basis-set profiles provide a visual assessment of the suitability of basis sets to describe electron-correlation effects. Furthermore, they provide the opportunity to assess the quality of the basis set as a whole-not only of the individual angular momentum subspaces, as is the case for the one-electron basis-set profiles. The two-electron completeness profiles of the cc-pVXZ (X = D, T, Q), aug-cc-pVTZ, cc-pCVTZ, and SVP-auxiliary basis sets for the carbon atom are presented as illustrative examples. (C) 2002 John Wiley Sons, Inc.