Improved ab initio effective core potentials for molecular calculations

Journal Article · Sat Dec 01 04:00:00 EST 1979 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.438197· OSTI ID:5773215

Christiansen, P A; Lee, Y S; Pitzer, K S

We have investigated the sources of error in bond lengths and dissociation energies computed from ab initio effective potentials derived from Phillips--Kleinman type pseudo-orbitals. We propose an alternate pseudo-orbital, effective potential treatment with the primary objective of agreement with all-electron molecular calculations. This new treatment forces the pseudo-orbitals to match precisely the Hartree--Fock orbitals in the valence region and thereby eliminates the major cause of error in the earlier calculations. Effective core potentials derived from these revised pseudo-orbitals were used to compute potential energy curves for the ground states of F/sub 2/, Cl/sub 2/, and LiCl and the results are compared with previous all-electron and effective potential calculations. Our effective potentials yield dissociation energies and bond lengths which are in excellent agreement with the all-electron values. Furthermore, in contrast to other procedures, our revised effective potentials result in an excellent description of the inner repulsive walls of the dissociation curves.

• Research Organization: Department of Chemistry and Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720
• OSTI ID: 5773215
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 71:11; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640300* -- Atomic
Molecular & Chemical Physics
74 ATOMIC AND MOLECULAR PHYSICS
ALKALI METAL COMPOUNDS
BOND LENGTHS
CHLORIDES
CHLORINE
CHLORINE COMPOUNDS
DISSOCIATION ENERGY
ELEMENTS
ENERGY
FLUORINE
HALIDES
HALOGEN COMPOUNDS
HALOGENS
LITHIUM CHLORIDES
LITHIUM COMPOUNDS
LITHIUM HALIDES
MOLECULAR ORBITAL METHOD
NONMETALS
POTENTIAL ENERGY