Floating basis functions in ab initio MO calculations: performance of the DIIS method and computation of vibrational contributions to electric properties

The DIIS method is shown to yield good convergence of the optimization of the Gaussian function centers in a floating basis set-based wavefunction. Floating functions are then used to compute Stark vibrational and intensity effects, along with vibrational contributions to static electrical properties of CO molecule. It is found that a floating DZ basis set shows a behavior similar to that of a DZP fixed, nuclei following basis set. (C) 1998 Published by Elsevier Science B.V. All rights reserved.