QUANTUM CHEMISTRY

James Francis Harrison Professor (b. 1940). B.S., 1962, Drexel Institute of Technology; M.A., 1964, Ph.D., 1966, Princeton University; NSF Postdoctoral Fellow, 1966-67, Research Associate 1967-68, Indiana University; Scientist in Residence, Argonne National Laboratory, 1980-81. 517-355-9715, Ext. 295 harrison@cem.msu.edu

I am interested in using ab-initio quantum chemistry to understand the electronic structure of atoms, molecules and solids. Because of advances in fundamental theory and computer technology, we are able to construct wavefunctions for atoms and molecules which are of unprecedented accuracy. We use these functions to assist in the interpretation of spectroscopic experiments and to develop and refine the qualitative notions of chemical bonding. Our current focus is to understand:

1.   The electronic structure of the ground and low-lying states of small molecules containing a transition metal atom. These molecules are of great interest as models for the nature of the transition - metal main group element chemical bond. We are also interested in the structure of the mono and dipositive ions of these systems.

2.   The nature of the molecular quadrupole moment and the information contained in these moments about the chemical bond. We have recently shown that the molecular quadrupole moment can be written as the sum of the quadrupole moments of the constituent atoms plus a term that depends on the shift in the electron density upon bond formation. In the course of this work we have defined the quadrupole moment density that shows where in the molecule the molecular contribution to the quadrupole moment comes from. We are extending these ideas to other one electron properties.

3.  The nature of the chemical bond in multiply charged ions like MH⁺⁺, MH₂⁺⁺, M⁺⁺ (H₂)_n, M⁺ⁿ (L)_m, etc. where M is Sc to Zn.

4.  The electronic and magnetic properties of crystalline transition metal oxides. We are presently studying the manganite La_xCa_1-xMnO₃ using ab-initio Hartree-Fock techniques. This is a collaborative project with Professors Mahanti and Kaplan from the MSU Physics Department.

5.  Several collaborative projects with members of the MSU chemistry department are underway. For example: "Mechanism of Fluorescence Quenching" with Professor V. McGuffin, "Mechanism of the Laser Induced Dissociation of CH₂Cl₂" with Professor M. Dantus; "Ab-Initio Studies of the Charge Density Susceptibility of the Water Molecule" and "Ab-Initio Studies of the Polarizability Induced by the Interaction of Two Hydrogen Molecules" with Professor K. Hunt.

Representative Publications

Crystal Hartree-Fock Calculations for La₂NiO₄ and La₂CuO₄, Yen-Sheng Su, T. A. Kaplan, S. D. Mahanti, and J. F. Harrison, Phys. Rev. B, 59, 10521 (1999).

Electronic Structure and Bonding in the Ground and Low Lying Excited States of the Dications ScH⁺⁺, TiH⁺⁺, VH⁺⁺, CrH⁺⁺, and MnH⁺⁺, J. F. Harrison and P. Christopher, Mol. Phys., 96, 31 (1999).

The Distance Dependence and Spatial Distribution of the Molecular Quadrupole Moments of P₂, S₂, and Cl₂, D. B. Lawson and J. F. Harrison, Mol. Phys., 93, 519 (1998).