Texas Tech University

Dr. William L. Hase

Title: Paul Whitfield Horn Professor, Robert A. Welch Chair

Education: Ph.D., New Mexico State University, 1970
Postdoctoral Study, New Mexico State University, 1970-71
Postdoctoral Study, University of California-Irvine, 1971-73

Research Area: Computational, Theoretical, and Physical Chemistry

Office: Chemistry 336

Phone: 806-834-3152

Fax: 806-742-1289

Email: bill.hase@ttu.edu

Research Group

Animations

Principal Research Interests

  • Theory of Unimolecular and Intramolecular Dynamics
  • Computer Simulation of Organic and Biochemical Reactions
  • Gas-Surface Collisions
  • Energy Transfer and Chemical Reactions at Interfaces
  • Web-based Computing
Dr. Hase’s research group simulates the dynamics of molecular motion and chemical reaction at an atomistic, microscopic level.  Classical, semi-classical, and quantum mechanical methods are used for the simulations, which are used to compare with experiments and to test and develop theoretical models of molecular motion and chemical reactivity.  Computer graphics are used to animate and visualize the simulations.  For many chemical problems classical mechanics provides an accurate description of atomic motion and the Hase research group has developed the VENUS computer program for performing classical trajectory simulations.  Calculating a classical trajectory or the motion of a semi-classical/quantum wave packet requires the derivatives of the potential energy with respect to the coordinates of each of the atoms.  In a direct dynamics simulation these derivatives are obtained directly from a quantum chemistry (QM) electronic structure theory.  To perform this type of simulation VENUS is interfaced with quantum chemistry computer programs.  For large-scale simulations, a QM/MM calculation may be performed in which part of the potential is represented by both a quantum mechanical theory and the remainder by molecular mechanical (MM) analytic potential energy functions.  Dr. Hase also advises computer science graduate students whose research is in the area of scientific computing; i.e. they develop computer programs for the simulations and structure the programs so that they run efficiently in a high-performance computing environment.  Dr. Hase is co-author of the books Chemical Kinetics and Dynamics and Unimolecular Reaction Dynamics. Theory and Experiments.

The current simulations of Dr. Hase’s research group include collision- and surface-induced dissociation (CID and SID) of ions (including peptides), the dynamics of gas phase SN2 nucleophilic substitution reactions, intramolecular and unimolecular dynamics of reactive intermediates, energy transfer and chemical reaction in collisions of ions and radicals with surfaces, structures of liquid surface interfaces, and adhesion, friction, lubrication, and wear of sliding surfaces.  The figure shown below is a chemical dynamics simulation of the SID of protonated diglycine.  The peptide shatters as it collides with the diamond {111} surface, forming H2 + NHCH2 + CONHCH2COOH+.



Representative Publications


"A Washboard with Moment of Inertia Model of Gas-Surface Scattering."Yan, T.-Y.; Hase, W.L.; Tully, J.C. J. Chem. Phys. 2004, 120, 1031.
"Energetics, Transition States, and Intrinsic Reaction Coordinates for Reactions Associated with O(3P) Processing of Hydrocarbon Surfaces."Yan, T.-Y.; Hase, W.L.; Doubleday, C. J. Chem. Phys. 2004, 120, 9253.
"Experiments with Parallelizing Tribology Simulations."Chaudhary, V.; Hase, W.L.; Jiang, H.; Sun, L.; Thaker, D. J. Supercomp. 2004, 28, 323.
"Direct Dynamics Study of N-Protonated Diglycine Surface-Induced Dissociation. Influence of Collision Energy."Wang, Y.; Song, K.; Hase, W.L. J. Amer. Soc. Mass Spec. 2003, 14, 1402.
"Role of Surface Intramolecular Dynamics in the Efficiency of Energy Transfer in Ne-Atom Collisions with an n-Hexythiolate Self-Assembled Monolayer."Yan, T.-Y.; Isa, N.; Gibson, K.A.; Sibener, S.J., Hase, W.L. J. Phys. Chem. A 2003, 107, 10600.
"Direct Dynamics Simulations.”Hase, W.L.; Song, K.; Gordon, M. Computing in Science and Engineering 2003, 5, 36.
"Trajectory Studies of SN2 Nucleophilic Substitution. 9. Microscopic Reaction Pathways and Chemical Kinetics for Cl- + CH3Br.”Wang, Y.; Hase, W.L.; Wang, H.  J. Chem. Phys. 2003, 118, 2688.
"Ab Initio Direct Dynamics of Cyclopropyl Radical Ring Opening.”Mann; D.J.; Hase, W.L.J. Am. Chem. Soc. 2002, 124, 3208.
"A SN2 Reaction that Avoids its Deep Potential Energy Minimum.”Sun, L.; Song, K.; Hase, W.L. Science 2002, 296, 875.

Contact

Department of Chemistry & Biochemistry