Professor Gregory A. Parker
Department of Physics & Astronomy
The University of Oklahoma

Research Vita - 2005

 

PHONE NUMBERS AND E-MAIL

Education:

Brigham Young University Chemistry (B.S.) 1973
Brigham Young University Mathematics 1973
Brigham Young University Chemistry (Ph.D.) 1976
California Institute of Technology Postdoctoral Fellow with Aron Kuppermann 1976-1978
University of Chicago Postdoctoral Fellow with John Light 1978-1980

 

MILITARY:

Oct. 1968 - Sep. 1969 Infantry Platoon Staff Sergeant (Grade E-6)
Company D 2nd Battalion, 12th Infantry, 25th Infantry Division, Vietnam
Awarded: The Bronze Star Medal for ``Meritorious Achievement in Ground and Operations Against Hostile Forces.''
Awarded: The Air Medal for ``Meritorious Achievement while participating and in Aerial Flight.''
National Defense Service Medal
Vietnam Service Medal
Vietnam Campaign Medal
Two Overseas Bars
Jun. 1968 - Sep. 1968 Platoon Sergeant, Fort Ord, California
Apr. 1968 - Jun. 1968 Non-Commissioned Officer School, Fort Benning, Georgia
Jan. 1968 - Apr. 1968 Advanced Infantry Training, Fort Polk, Louisiana
Nov. 1967 - Jan. 1968 Basic Training, Fort Lewis, Washington

 

PROFESSIONAL EXPERIENCE:

1989-Present Professor,
Department of Physics and Astronomy,
University of Oklahoma
1977-Present Visiting Staff Member,
Los Alamos Scientific Laboratory
1994-1995 Visiting Research Fellow, University of Houston,
Department of Chemistry
1987-1988 Associated Western Universities Fellow,
Los Alamos National Laboratory
1984-1989 Associate Professor,
Department of Physics and Astronomy,
University of Oklahoma
1985-1986 Associated Western Universities Fellow,
Los Alamos National Laboratory
1980-1984 Assistant Professor,
Department of Physics and Astronomy,
University of Oklahoma
1978-1980 Postdoctoral Research Fellow in Chemistry,
University of Chicago
1976-1978 Postdoctoral Research Fellow in Chemistry,
California Institute of Technology
1975-1976 Associated Western Universities Fellow,
Los Alamos National Laboratory


PROFESSIONAL SOCIETY MEMBERSHIPS:

ACADEMIC HONORS:

1992 The Regent's Award for Superior Accomplishment in Research and Creative Activity
1988 University of Oklahoma Associate's Distinguished Lectureship Award
1987 University of Oklahoma Associate's Distinguished Lectureship Award
1986 University of Oklahoma Associate's Distinguished Lectureship Award
1985 Sigma Xi Research Award
1984 University of Oklahoma Associate's Distinguished Lectureship Award
1970 John Einar Anderson Scholarship

 


POSTDOCTORAL FELLOWS:

GRADUATE STUDENTS:

UNDERGRADUATE STUDENTS

HOBBIES:

COLLABORATORS

Prof. Zlatko Bacic
Department of Chemistry
New York University
4 Washington Place
New York, New York 10003		 Prof. Antonio Lagana
Dipartimento di Chimica
Universita di Perugia, Perugia, Italy
Prof. David E. Golden
P.O. Box 305370
University of North Texas
Denton, Texas 76203-5370		 Prof. John C. Light
Deptartmentof Chemistry and
The James Franck Institute
University of Chicago
Chigago, Illinois 60637
Prof. David K. Hoffman
Department of Chemistry and
Ames Laboratory
Iowa State University
Ames, Iowa 50011		 Dr. Thomas M. Miller
Air Force Research Laboratory, VSBP
29 Randolf Rd
Hanscomb AFB, MA 01731-3010
Prof. Ronald Kantowski
Department of Physics and Astronomy
University of Oklahoma
Norman, Oklahoma 73019		 Prof. Michael A. Morrison
Department of Physics and Astronomy
University of Oklahoma
Norman, Oklahoma 73019
Prof. Mark Keil
Department of Physics and Astronomy
University of Oklahoma
Norman, Oklahoma 73019		 Dr. Russell T Pack
Group T-12, MS-J569
P.O. Box 1663
Los Alamos National Laboratory
Los Alamos, NM 87545
Dr. Brian K. Kendrick
Group T-12, MS-J569
P.O. Box 1663
Los Alamos National Laboratory
Los Alamos, NM 87545		 Prof. Stewart Ryan
Department of Physics and Astronomy
University of Oklahoma
Norman, Oklahoma 73019
Prof. Donald J. Kouri
Department of Chemistry and
Department of Physics
University of Houston
Houston, Texas 77004		 Prof. James S. Shaffer
Department of Physics and Astronomy
University of Oklahoma
Norman, Oklahoma 73019
Dr. Joel D. Kress
Group T-12, MS-J569
P.O. Box 1663
Los Alamos National Laboratory
Los Alamos, NM 87545		 Prof. Richard L. Snow
Department of Chemistry
Brigham Young University
Provo, Utah 84602
Prof. Aron Kuppermann
Department of Chemistry
California Institute of Technology
Pasadena, California 91125		 Dr. Robert B. Walker
Group T-12, MS-J569
P.O. Box 1663
Los Alamos National Laboratory
Los Alamos, NM 87545

 

PUBLICATIONS

FREQUENTLY CITED PUBLICATIONS (more than 100 citations each)

DISTRIBUTED COMPUTER PROGRAMS

VIDEOS

INVITED LECTURES

FUNDING HISTORY

Research Interests:

Rotational Decoupling Approximations


A fundamental quantity often measured by experimentalists is the collision cross section which determines the effective size of the colliding particles. In an inelastic collision of an atom with a diatomic molecule many vibrational and rotational states are strongly coupled together. The equations are difficult to solve and hence requires massive amounts of computer time. We became interested in these processes and showed that an Infinite Order Sudden Approximation (IOSA) was accurate enough for many purposes. We then showed that one can drastically simplify the expressions for various cross sections. It was demonstrated that within this approximation one could view the collision of an atom with a diatomic molecule as fixed orientation collisions. That is, the collision can occur before the molecule has time to rotate. Hence, these simplified cross section formulae are angular averages of the fixed orientation results. One of my papers in this area was the most cited article in the {\it Journal of Chemical Physics} and was the second most cited article in the area of Atomic and Molecular Physics during 1978 and 1979.\footnote{$\dagger$} {Eugene Garfied - Current Contents -- Articles Most cited in 1978 and 1979 -- G. A. Parker and R. T Pack, ``Rotationally and Vibrationally Inelastic Scattering in the Rotational IOS Approximation. Ultrasimple Calculation of Total (Differential, Integral, and Transport) Cross Sections for Nonspherical Molecules'', {\it J. Chem. Phys.} {\bf 68}, 1585-1601 (1978).} Derived simplified differential cross section formulas and identified the partial-wave parameter in the J$_z$--CCS approximation for molecular scattering. Developed ultrasimple methods for calculation of Total (Differential, Integral and Transport) cross sections for nonspherical molecules in the Infinite Order Sudden Approximation (IOS).

  • T. P. Tsein, G. A. Parker and R. T Pack, ``Rotationally Inelastic Molecular Scattering. Computational Tests of
    Some Simple Solutions of the Strong Coupling Problem'', {\it J. Chem. Phys.} {\bf 59}, 5373-5381 (1973).
  • G. A. Parker and R. T Pack, ``Identification of the Partial-Wave Parameter and Simplification of the Differential Cross Section in the J$_{z}$-CCS Approximation in Molecular Scattering'', {\it J. Chem. Phys.} {\bf 66}, 2850-2853 (1977).
  • G. A. Parker and R. T Pack, ``Rotationally and Vibrationally Inelastic Scattering in the Rotational IOS Approximation. Ultrasimple Calculation of Total (Differential, Integral, and Transport) Cross Sections for Nonspherical Molecules'', {\it J. Chem. Phys.} {\bf 68}, 1585-1601 (1978).

Intermolecular Potentials


Developed an electron-gas method for calculating intermolecular potentials from electron densities. This method assumed that the electrons formed a uniform electron gas and gave reasonable results for short range interactions. The long range interactions were obtained from van der Waals interactions obtained from frequency dependent polarizabilities using Pade approximates.

  • G. A. Parker, R. L. Snow and R. T Pack, ``Calculation of Molecule-Molecule Intermolecular Potentials Using Electron Gas Methods'', {\it Chem. Phys Lett.} {\bf 33}, 399-403 (1975).
  • G. A. Parker and R. T Pack, ``van der Waals Interactions of Carbon Monoxide'', {\it J. Chem. Phys.} {\bf 64}, 2010-2012 (1976).
  • G. A. Parker, R. L. Snow and R. T Pack, ``Intermolecular Potential Surfaces from Electron Gas Methods. I. Angle and Distance Dependence of the $He+CO_{2}$ and $Ar+CO_{2}$ Interactions'', {\it J. Chem Phys.} {\bf 64}, 1668-1678 (1976).

Infinite Order Sudden Analysis of Differential Cross Section Data


Showed that the central field potentials fit to experimental data for highly anisotropic collision partners {\it do not} correspond to the spherical average of the intermolecular potential. Developed a simplified procedure using the IOSA for determining reliable and accurate intermolecular potentials from crossed molecular beam experiments. This method is now routinely used by experimentalist throughout the world for analysis of total differential cross section data. Using our multi-property fitting method one can obtain accurate anisotropic intermolecular potentials from experimental data.

  • M. Keil, G. A. Parker and A. Kuppermann, ``An Empirical Anisotropic Intermolecular Potential for $He+CO_{2}$'' {\it Chem. Phys. Lett.} {\bf 59}, 443-448 (1978).
  • G. A. Parker, M. Keil and A. Kuppermann, ``Scattering of Thermal He Beams by Crossed Atomic and Molecular Beams.V. Anisotropic Intermolecular Potentials for $He+ CO_{2},N_{2}O$ and $C_{2}N_{2}$'',
  • {\it J. Chem. Phys.} {\bf 78}, 1145-1162 (1983). M. Keil and G. A. Parker, ``Empirical Potential for the $He+CO_{2}$ Interaction: Multi-property Fitting in the Infinite-Order Sudden Approximation.'', {\it J. Chem. Phys.} {\bf 82}, 1947-1966 (1985).

Solution of Coupled Differential Equations


Developed the VIVAS method which is an efficient and accurate method for solving the coupled differential equations encountered in quantum scattering.

  • G. A. Parker, T. G. Schmalz and J. C. Light, ``A Variable Interval Variable Step Method for the Solution of Coupled Second Order Differential Equations'', {\it J. Chem. Phys.} {\bf 73}, 1757-1764 (1980).
  • G. A. Parker, J. C. Light and B. R. Johnson, ``The Logarithmic Derivative-Variable Interval Variable Step Hybrid Method for the Solution of Coupled Linear Second Order Differential Equations'', {\it Chem. Phys. Lett.} {\bf 73}, 572-575 (1980).

Discrete Variable Representation


Contributed to the development of the Discrete Variable Representataion (DVR) method which is widely used in molecular scattering. In this representation the potential is diagonal and the kinetic energy operator provides the coupling between different quantum states. The Hamiltonian can be easily constructed and efficiently stored.

  • J. V. Lill, G. A. Parker and J. C. Light, ``Discrete Variable Representations and Sudden Models in Quantum Scattering Theory'', {\it Chem. Phys. Lett.} {\bf 89}, 483-489 (1982).
  • J. V. Lill, G. A. Parker and J. C. Light, ``The Discrete Variable-Finite Basis Approach to Quantum Scattering'' {\it J. Chem. Phys.} {\bf 85}, 900-910 (1986).

Angular Correlation


Derived expressions for analysis of angular correlation experiments.

Reactive Scattering


Reactive scattering processes form the heart of chemistry and the quantum theory thereof is one of the most important problems in theoretical chemistry or theoretical atomic and molecular physics. We developed the theory and computer code for reactive scattering using Adiabatically-adjusting Principal-axis Hyperspherical (APH) coordinates. We produce essentially exact bench mark results on a variety of chemically interesting reactions. We have contributed significantly to current understanding of reactive scattering. We have seen that quantum resonances are very common and may dominate most chemical reactions. We have been the first to calculate state-to-state results for the following systems:

  • $$F+H_2 \rightleftharpoons H+FH $$
  • $$e^++H \rightleftharpoons p^++Ps$$
  • $$He+H_2^+ \rightleftharpoons HeH^++H$$
  • $$Li+FH \rightleftharpoons LiF+H$$
  • $$H+O_2 \rightleftharpoons O+OH$$

References

  • G. A. Parker, R. T Pack, B. J. Archer and R. B. Walker, ``Quantum Reactive Scattering in Three Dimensions using Hyperspherical (APH) Coordinates. Test on $H+H_{2}$ and $D+H_{2}$.'' {\it Chem. Phys. Lett.} {\bf 137}, 564-568 (1987).
  • R. T Pack and G. A. Parker, ``Quantum Reactive Scattering in Three Dimensions Using Hyperspherical (APH) Coordinates. II. Theory.'' {\it J. Chem. Phys.} {\bf 87}, 3888-3921 (1987).
  • J. D. Kress, Z. Bacic, G. A. Parker and R. T. Pack, ``Quantum Effects in the $F+H_{2} \rightleftharpoons HF+H $ Reaction. Accurate 3D Calculations with a Realistic Potential Energy Surface.'' {\it Chem. Phys. Lett.} {\bf 157}, 484-490 (1989).
  • B. J. Archer, G. A. Parker and R. T Pack, ``Positron-Hydrogen Atom S-Wave Coupled Channel Scattering at Low Energies''. {\it Phys. Rev. Lett.} {\bf 41}, 1303-1310 (1990).
  • Z. Bacic, J. D. Kress, G. A. Parker and R. T Pack, ``Quantum Reactive Scattering in Three Dimensions Using Hyperspherical (APH) Coordinates. IV. Discrete Variable Representation (DVR) Basis Functions and the Analysis of Accurate Results for $F+H_{2}$ ''. {\it J. Chem. Phys. } {\bf 92}, 2344-2361 (1990).
  • A. Lagan\`a, R. T Pack, and G. A. Parker, ``Li+FH Reactive Cross Sections From J=0 Accurate Quantum Reactivity'' {\it J. Chem. Phys.} {\bf 99}, 2269-2270 (1993).
  • R. T Pack, E. A. Butcher and G. A. Parker, ``Accurate Quantum Probabilities and Threshold Behavior of the $H+O_{2}$ Combustion Reaction''. {\it J. Chem. Phys.} {\bf 99}, 9310-9313 (1993) (Rapid Communication).
  • C. Y. Yang, S. J. Klippenstein, J. D. Kress, R. T Pack, G. A. Parker, and A. Lagan\`a, ``Comparison of Transition State Theory with Quantum Scattering Theory for the Reaction $Li+HF \rightleftharpoons LiF+H$, {\it J. Chem. Phys.}, {\bf 100}, 4917-4924 (1994).
  • G. A. Parker, A. Lagan\`a, S. Croccianti, and R. T Pack, ``A Detailed 3D Quantum Study of the $Li+HF$ Reaction.'' {\it J. Chem. Phys.}, {\bf 102} 1238-1250 (1995).
  • R. T Pack, E. A. Butcher, and G. A. Parker, ``Accurate 3D Quantum Probabilities and Collision Lifetimes of the $H+O_2$ Combustion Reaction,'' {\it J. Chem. Phys.}, {\bf 102} 5998-6012 (1995).

Reactive Scattering Simulations.


In collaborations with Molecular Beam Experimentalist Prof. Mark Keil we have implemented a computer program for fully simulating the experimental characteristics in his laboratory. This enables direct comparisons of theoretically calculated differential cross sections to measured laboratory frame angular distributions. Thus it is no longer necessary to de-convolute the measured angular distributions.

  • G. Dharmasena, T. R. Phillips, K. N. Shokhirev, G. A. Parker and M. Keil,``Vibrationally and Rotationally Resolved Angular Distributions for $F+H_2\rightleftharpoons HF(\nu^\prime,j^\prime)+H$ Reactive Scattering.'' {\it J. Chem. Phys.}, {\bf 106}, 9950-9953, (1997). (Rapid Communication)
  • G. Dharmasena, K. A. Copeland, J. A. Young, R. A. Lasell, T. R. Phillips, G. A. Parker and M. Keil, ``Angular Dependence for the $\nu^\prime j^\prime$ -- Resolved States in $F+H_2\rightleftharpoons HF+H$ Scattering.'' {\it J. Phys. Chem.}, {\bf 101}, 6429-6440, (1997).
  • G. Dharmasena, T. R. Phillips, G. A. Parker and M. Keil, ``Angular Distributions for Specific $HF$ Vib-Rotational States from $F+H_2\rightleftharpoons HF+H$ Reactive Scattering.'' To be submitted to the Journal of Chemical Physics.

Distributed Approximating Functionals


Contributed to the understanding of Distributed Approximating Functionals.

  • W. Zhu, Y. Huang, G. A. Parker, D. J. Kouri, and D. K. Hoffman, ``Application of Distributed Approximating Functionals for Atom-Rigid Rotor Inelastic Scattering: Body Frame Close-Coupling Time-Dependent and Time-Independent Wavepacket Approaches.'' {\it J. Phys. Chem.}, {\bf 98}, 12516-12520 (1994).
  • D. J. Kouri, W. Zhu, G. A. Parker and D. K. Hoffman, ``Accelleration of Convergence in the Polynomial-Expanded Spectral Density Approach to Bound and Resonance State Calculations.''
  • S. S. Iyengar, G. A. Parker, D. J. Kouri, and D. K. Hoffman ``Symmetry Adapted Distributed Approximating Functionals:
    Theory and Application to the ro-vibrational states of $H_3^+$.'' {\it J. Chem. Phys.}, {\bf 110}, 10283-10298, (1999).
  • K. Zhang, G. A. Parker, D. J. Kouri, D. K. Hoffman, S. S. Iyengar ``Quantum Reactive Scattering in Three Dimensions using Hyperspherical (APH) Coordinates: Periodic Distributed Approximating Functional (PDAF) Method for Surface Functions.'' {\it J. Chem. Phys.} {\bf }, 569-581 (2003).

Iterative Diagonalizations of Large Matrices


Developed the Spectral Density method for iterative solution of the matrix eigenvalue problem.

  • D. J. Kouri, W. Zhu, G. A. Parker and D. K. Hoffman, ``Accelleration of Convergence in the Polynomial-Expanded Spectral Density Approach to Bound and Resonance State Calculations.'' {\it Chem. Phys. Lett.}, {\bf 238} 395-403 (1995).
  • G. A. Parker, W. Zhu, Y. H. Huang, D. K. Hoffman, and D. J. Kouri, ``Matrix Pseudo-Spectroscopy -- Iterative Calculation of Matrix Eigenvalues and Eigenvectors of Large Matrices Using a Polynomial Expansion of the Dirac Delta-Function.'' {\it Comp. Phys. Comm.}, {\bf 96} 27-35 (1996).

TEACHING GOALS

I enjoy teaching and allocate the time necessary to prepare excellent lectures. I also give a fair number of demonstrations for the students to motivate them. It is absolutely necessary to present a simple picture of the science, emphasizing a physical understanding of the concepts. It is also necessary to get the students actively involved in the learning process, to regularly evaluate their understanding and make changes as necessary.

I have taught classes with as few as three students and as many as 246 students both at the graduate and undergraduate levels. I try to be fair and equitable at all times. I also make sure that the students know the grade they are earning throughout the semester by giving them progress reports weekly.

Stewart Ryan, Ron Kantowski and myself have been awarded an NSF undergraduate education grant for the {\it Production of Short, Animated Audio/Visual Instructional Aids for Physics which Illustrate the Application of Physics to Technology}. We have acquired professional video equipment and are currently producing animated videos for classroom instruction. Our ``Physics Video Project'' is an ongoing project has several undergraduate students involved. I have enclosed two copies of the video ``The Audio CD'' we produced. We have involved students from art who enthusiastically produce the animations and have a {\it commercial} for their vita. These art students are now enjoying rewarding careers in the commercial industry. We have involved undergraduate physics and zoology students that enjoy describing the science in a simple and entertaining manner. It is my desire to produce other animations as described in my cover letter.

I have been a successful teacher and will continue to make my courses interesting, challenging and intriguing to each student. If I don't enjoy my course, I figure the students will enjoy it even less and therefore I try to make each lecture interesting to myself as well.

Graduate Courses Taught

Undergradute Courses Taught

Professor Gregory A. Parker
440 West Brooks
Department of Physics and Astronomy
University of Oklahoma
Norman, OK 73019

 

 

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