Theory of transition-metal complexes

Unrestricted Hartree-Fock molecular-orbital method and its application to KNiF3

D. E. Ellis, Arthur J Freeman, P. Ros

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

The unrestricted Hartree-Fock molecular-orbital self-consistent-field (MO-SCF) method is developed and applied to the problem of transition-metal ion clusters. This method removes many of the shortcomings of earlier treatments and provides, in principle, a framework for obtaining fairly accurate and meaningful results. Model calculations are reported for the KNiF3 system, in which all matrix elements of the Hamiltonian are accurately computed (by the choice of a special one-center basis set) for all the electrons of the molecular cluster. Considerable variational freedom is allowed in all representations; as a consequence, significant covalent mixing is found for representations containing the metal 3s and 3p orbitals. This molecular-orbital approach thus differs greatly from the previous approach of using molecular orbitals formed as linear combination of atomic orbitals (MO-LCAO); in particular, it is emphasized that the simple (and inadequate) single-variational-parameter LCAO treatment of earlier calculations is replaced by full HF-SCF calculations in a multielectron framework including all electrons (and not just the bonding and antibonding electrons as in earlier treatments). Complete SCF calculations are carried out for both the (NiF6)4- and the (Ni2F)3+ clusters (representing the metal-ion and the ligand-ion point of view, respectively) including the effects of an external crystalline field. Although these first (crude) calculations suffer from limited basis size, reasonable agreement with experiment is found for such quantities as the optical-splitting parameter 10Dq, the transferred hyperfine interaction, and the neutron magnetic form factor.

Original languageEnglish
Pages (from-to)688-707
Number of pages20
JournalPhysical Review
Volume176
Issue number2
DOIs
Publication statusPublished - 1968

Fingerprint

molecular orbitals
transition metals
self consistent fields
metal ions
orbitals
electrons
molecular clusters
form factors
neutrons
ligands
matrices
metals
ions
interactions

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Theory of transition-metal complexes : Unrestricted Hartree-Fock molecular-orbital method and its application to KNiF3. / Ellis, D. E.; Freeman, Arthur J; Ros, P.

In: Physical Review, Vol. 176, No. 2, 1968, p. 688-707.

Research output: Contribution to journalArticle

@article{395344e4239d4b4a81827498a70ee07f,
title = "Theory of transition-metal complexes: Unrestricted Hartree-Fock molecular-orbital method and its application to KNiF3",
abstract = "The unrestricted Hartree-Fock molecular-orbital self-consistent-field (MO-SCF) method is developed and applied to the problem of transition-metal ion clusters. This method removes many of the shortcomings of earlier treatments and provides, in principle, a framework for obtaining fairly accurate and meaningful results. Model calculations are reported for the KNiF3 system, in which all matrix elements of the Hamiltonian are accurately computed (by the choice of a special one-center basis set) for all the electrons of the molecular cluster. Considerable variational freedom is allowed in all representations; as a consequence, significant covalent mixing is found for representations containing the metal 3s and 3p orbitals. This molecular-orbital approach thus differs greatly from the previous approach of using molecular orbitals formed as linear combination of atomic orbitals (MO-LCAO); in particular, it is emphasized that the simple (and inadequate) single-variational-parameter LCAO treatment of earlier calculations is replaced by full HF-SCF calculations in a multielectron framework including all electrons (and not just the bonding and antibonding electrons as in earlier treatments). Complete SCF calculations are carried out for both the (NiF6)4- and the (Ni2F)3+ clusters (representing the metal-ion and the ligand-ion point of view, respectively) including the effects of an external crystalline field. Although these first (crude) calculations suffer from limited basis size, reasonable agreement with experiment is found for such quantities as the optical-splitting parameter 10Dq, the transferred hyperfine interaction, and the neutron magnetic form factor.",
author = "Ellis, {D. E.} and Freeman, {Arthur J} and P. Ros",
year = "1968",
doi = "10.1103/PhysRev.176.688",
language = "English",
volume = "176",
pages = "688--707",
journal = "Physical Review",
issn = "0031-899X",
publisher = "American Institute of Physics Publising LLC",
number = "2",

}

TY - JOUR

T1 - Theory of transition-metal complexes

T2 - Unrestricted Hartree-Fock molecular-orbital method and its application to KNiF3

AU - Ellis, D. E.

AU - Freeman, Arthur J

AU - Ros, P.

PY - 1968

Y1 - 1968

N2 - The unrestricted Hartree-Fock molecular-orbital self-consistent-field (MO-SCF) method is developed and applied to the problem of transition-metal ion clusters. This method removes many of the shortcomings of earlier treatments and provides, in principle, a framework for obtaining fairly accurate and meaningful results. Model calculations are reported for the KNiF3 system, in which all matrix elements of the Hamiltonian are accurately computed (by the choice of a special one-center basis set) for all the electrons of the molecular cluster. Considerable variational freedom is allowed in all representations; as a consequence, significant covalent mixing is found for representations containing the metal 3s and 3p orbitals. This molecular-orbital approach thus differs greatly from the previous approach of using molecular orbitals formed as linear combination of atomic orbitals (MO-LCAO); in particular, it is emphasized that the simple (and inadequate) single-variational-parameter LCAO treatment of earlier calculations is replaced by full HF-SCF calculations in a multielectron framework including all electrons (and not just the bonding and antibonding electrons as in earlier treatments). Complete SCF calculations are carried out for both the (NiF6)4- and the (Ni2F)3+ clusters (representing the metal-ion and the ligand-ion point of view, respectively) including the effects of an external crystalline field. Although these first (crude) calculations suffer from limited basis size, reasonable agreement with experiment is found for such quantities as the optical-splitting parameter 10Dq, the transferred hyperfine interaction, and the neutron magnetic form factor.

AB - The unrestricted Hartree-Fock molecular-orbital self-consistent-field (MO-SCF) method is developed and applied to the problem of transition-metal ion clusters. This method removes many of the shortcomings of earlier treatments and provides, in principle, a framework for obtaining fairly accurate and meaningful results. Model calculations are reported for the KNiF3 system, in which all matrix elements of the Hamiltonian are accurately computed (by the choice of a special one-center basis set) for all the electrons of the molecular cluster. Considerable variational freedom is allowed in all representations; as a consequence, significant covalent mixing is found for representations containing the metal 3s and 3p orbitals. This molecular-orbital approach thus differs greatly from the previous approach of using molecular orbitals formed as linear combination of atomic orbitals (MO-LCAO); in particular, it is emphasized that the simple (and inadequate) single-variational-parameter LCAO treatment of earlier calculations is replaced by full HF-SCF calculations in a multielectron framework including all electrons (and not just the bonding and antibonding electrons as in earlier treatments). Complete SCF calculations are carried out for both the (NiF6)4- and the (Ni2F)3+ clusters (representing the metal-ion and the ligand-ion point of view, respectively) including the effects of an external crystalline field. Although these first (crude) calculations suffer from limited basis size, reasonable agreement with experiment is found for such quantities as the optical-splitting parameter 10Dq, the transferred hyperfine interaction, and the neutron magnetic form factor.

UR - http://www.scopus.com/inward/record.url?scp=0000563676&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000563676&partnerID=8YFLogxK

U2 - 10.1103/PhysRev.176.688

DO - 10.1103/PhysRev.176.688

M3 - Article

VL - 176

SP - 688

EP - 707

JO - Physical Review

JF - Physical Review

SN - 0031-899X

IS - 2

ER -