Accession Number : ADA329569

Title :   Novel Electron Correlation Methods: Multiconfigurational Density Functional Theory.

Descriptive Note : Final technical rept. 15 Jul 96-14 Apr 97,

Corporate Author : SCHRODINGER INC PORTLAND OR

Personal Author(s) : Ringnalda, Murco N.

PDF Url : ADA329569

Report Date : 14 APR 1997

Pagination or Media Count : 20

Abstract : The multiconfigurational density functional theory (MCDFT) software Schrodinger, Inc. has developed in Phase I of this project combines many of the advantages of generalized valence bond (GVB) and restricted configuration interaction (RCI) techniques with those of DFT. We have explored several avenues for improving the implementation of MCDFT methods and have incorporated the MCDFT code into a development version of our commercially successful electronic structure program, PS-GVB. The work we have performed in Phase I has centered upon these five tasks; partitioning of the GVB two-electron energy into Coulomb, exchange, and intra-pair terms; coding and developing GVB-RCI-DFT (post-SCF DFT on a GVB-RCI density); inclusion of self-inter action-corrected (SIC) density functionals; optimization of hybrid MCDFT methods; and generation of a preliminary version of fully self-consistent GVB-DFT. The procedure we employed to accomplish each of these tasks is described in this report, along with MCDFT results for computation of chemical properties. Our Phase I result's are highly encouraging, demonstrating the MCDFT approaches are camable of significantly improved accuracy as compared to current DFT functionals. The N3 or better scaling with basis set size for PS-GVB's methods resulting from its use of the pseudospectral (PS) algorithm ensures that MCDFT is practical for reasonable-sized systems as well. Although considerable additional work will be required in Phase II to implement fully self-consistent MCDFT methods, fund the optimum functional (or functionals), improve computational efficiency, and define protocols for utilizing GVB wavefunctions in a localized region of the molecule, the preliminary software clearly demonstrates that the basic multiconfigurational density functional theory is sound.

Descriptors :   *COVALENT BONDS, *ELECTRONIC STATES, *CONFIGURATIONS, MATHEMATICAL MODELS, ALGORITHMS, SOFTWARE ENGINEERING, CHEMICAL PROPERTIES, CODING, ELECTRON ENERGY, CORRELATION, HYBRID SYSTEMS, WAVE FUNCTIONS.

Subject Categories : Physical Chemistry
      Computer Programming and Software

Distribution Statement : APPROVED FOR PUBLIC RELEASE