James Harrison
Professor Office: 37 A Chemistry
Phone: 517-355-9715 295 /
Websites: Research Group - Area
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Quantum Chemistry
(Research Description PDF - 909 kb)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:
The electronic structure of the ground and low-lying states of small molecules containing a transition metal atom. Diatomics of interest include MX where M is a transition metal (Sc to Zn) and X is a main group element (H to CL). These molecules are of great interest as models for the nature of the transition metal - main group element chemical bond. Triatomics include the metal carbynes MCH, the understanding of which is fundamental to the reactions of transition metals with hydrocarbons. We are also interested in the structure of the mono and dipositive ions of these systems.
The nature of molecular multipole moments and the information contained in these moments about the chemical bond. While we all have an instinctive feeling about the meaning of a molecular dipole moment and how it reflects the charge distribution in a molecule the same instincts often fail when considering for example, the quadrupole moment. Some of this problem is that the quadrupole moment is a second rank tensor while the dipole moment is a tensor of the first rank. However even for homonuclear diatomics where the quadrupole tensor has only one unique component the relationship between this component and the molecular charge density is not well understood. 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 like the electric field gradient at a particular nucleus and the dipole moment (still more to learn!).
Selected Publications
Electronic Structure of Diatomic Molecules Composed of a First-Row Transition Metal and Main-Group Element (H-F), J.F. Harrison, Chem. Rev. 2000, 100, 679.On the Representation of Molecular Quadrupole Moments in terms of Atomic Moments, J.F. Harrison, J. Phys. Chem. A 2005, 109, 5492-5497.
Relationship Between the Charge Distribution and Dipole Moment of Co and the Related Molecules Cs, SiO, SiS, J.F. Harrison., J. Phys. Chem. A 2006, 110, 10848-10857.
The Collision-induced Polarizability of a Pair of Hydrogen Molecules, X. Li, C. Ahuja, J.F. Harrison, K.L.C. Hunt, J. Chem. Phys. 2007, 126, 214302.
Scanning-probe Spectroscopy of Semiconductor Donor Molecules, I. Kuljanishvili, C. Kayis, J.F. Harrison, C. Piermarocchi, T.A. Kaplan, S.H. Tessmer, L.N. Pfeiffer, K.W. West, Nature Phys. March 2008, 4, 227-233.
The Geometry, Vibrational Frequencies, Thermochemistry, Quadrupole Moments and Electronic Structure of C2Na2: Comparison with C2Li2, C2H2, C2F2 and C2Cl2, D.J. Gearhart, K.L.C. Hunt, J.F. Harrison, J. Mol. Struc.: THEOCHEM 2008, 858, 31?38.
Dipole and Quadrupole Moment Functions of the Hydrogen Halides, HF, HCl, HBr, and HI: A Hirshfeld Interpretation, J.F. Harrison, J. Chem. Phys. 2008, 128, 114320.
