On the resolution of identity Coulomb energy approximation in density functional theory

The Resolution of the Identity approximation for the Coulomb (RI-J) energy in Density Functional Theory improves the computational efficiency of large -scale calculations but requires the use of a second, or "auxiliary" basis set. We examine the performance of some of the existing auxiliary basis set s with a variety of basis sets and molecules. We determine the accuracy of the RI-J approximation for these basis sets and suggest criteria for the se lection of combinations of basis set and auxiliary basis set. (C) 2000 Else vier Science B.V. All rights reserved.