Improved ab initio effective core potentials for molecular calculations
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), Vol. 71:11
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHLORINE
POTENTIAL ENERGY
FLUORINE
LITHIUM CHLORIDES
MOLECULAR ORBITAL METHOD
BOND LENGTHS
DISSOCIATION ENERGY
ALKALI METAL COMPOUNDS
CHLORIDES
CHLORINE COMPOUNDS
ELEMENTS
ENERGY
HALIDES
HALOGEN COMPOUNDS
HALOGENS
LITHIUM COMPOUNDS
LITHIUM HALIDES
NONMETALS
640300* - Atomic
Molecular & Chemical Physics