# Professor Gregory A. ParkerDepartment of Physics & AstronomyThe 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:

• Sigma Xi
• American Chemical Society
• Division Theoretical Chemistry of the American Chemical Society
• American Physical Society
• Division of Electron and Atomic Physics of the American Physical Society

 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:

• Zlatko Bacic
• Joel D. Kress
• Timothy R. Phillips
• Stefano Crocchianti

• Daniel Brue -- Three-Body Recombination at Ultracold Temeratures
• Xaun Li -- Coherent Control of Molecular Collisions
• Bill Archer -- Positron-Hydrogen Atom Scattering -- Ph.D. 1988
• Sin-Tarng Chang -- Laser Induced Collisional Energy Transfer -- Ph.D. 1989.

• Bill Archer -- Reactive Scattering and Differential Cross Sections
• Christopher Aubin -- NSF Research Experience for Undergraduates
• Jason Bagby -- Physcis Video Project
• Luke Burris -- Physcis Video Project
• David Burton -- Physcis Video Project
• Eric Butcher -- Quantum Reactive Scattering
• Heidi Clark -- NSF Research Experience for Undergraduates
• Gregory Cowin -- Computer Graphics
• Matt Grice -- Physcis Video Project
• Jonathan Handy -- Distributed Approximating Functions
• J. J. Kuhn -- Physcis Video Project
• David LeCrone -- Physcis Video Project
• Steven G. Parker -- Ray-Trace Imaging and Video Production
• Michael A. Parker -- One Dimensional Quantum Wells
• Kirill Shokhirev -- NSF Research Experience for Undergraduates
• Houston Spitler -- Physcis Video Project
• Kirk VanOpdorp -- NSF Research Experience for Undergraduates
• Paul Warfel -- Physics Video Project
• Adrean Webb -- Physcis Video Project and Distributed Approximating Functions
• Daniel Brue -- Molecular Potential Energy Surfaces

### HOBBIES:

• Family Vacations
• Family History and Genealogy
• Birdwatching
• Racquetball
• Wildlife Photography
• Sport Photography

### 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

• D. A. Brue, X. Li, and G. A. Parker, Conical Intersection between the Lowest Spin-Aligned $Li_3{{^4A^\prime}}$ Potential Energy Surfaces'', Submitted for publication: {\it Phys. Rev. Lett.}
• F. D. Colavecchia, F. Mrugala, G. A. Parker and R. T Pack, Accurate Quantum Calculations on Three-Body Collisions in Recombination and Collision-Induced Dissociation II. An Improved Propagator.'' {\it J. Chem. Phys.} {\bf 118} 10387-10398 (2003).
• F. D. Colavecchia, J. P. Burke, W. Stevens, M. R. Salazar, G. A. Parker and R. T Pack, The Potential Energy Surface for Spin-Aligned $Li_3$ ($1{{^4}A^\prime}$) and the Potential Energy Curve for Spin-Aligned $Li_2$ ($a{^3}\Sigma_u^+$).'' {\it J. Chem. Phys.} {\bf 118}, 5484-5495 (2003).
• 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 118}, 569-581 (2003).
• G. A. Parker, F. D. Colavecchia, and R. T Pack, Theoretical Treatment of Three-Body Collisions in Recombination and Collision-Induced Dissociation.'' in P. Soldán, M. T. Cvitas, J. M. Hutson and C. S. Adams (editors),"Interactions Between Cold Atoms and Molecules", published by CCP6, Daresbury (2002). ISBN 0-9522736-9-1
• G. A. Parker, R. B. Walker, B. K. Kendrick and R. T Pack, Accurate Quantum Calculations on Three-Body Collisions in Recombination and Collision-Induced Dissociation I. Converged Probabilities for the $H+Ne_2$ System.'' {\it J. Chem. Phys.} {\bf 117}, 6083-6102 (2002).
• N. Shafer-Ray, G. A. Parker and M.A. Morrison, A Classical Ensemble Model of Three-Body Collisions in the Point Contact Approximation and Application to Alignment Effects in Near-Resonant Energy Transfer Collisions of $He$ Atoms with Rydberg $Ca$ Atoms.'' {\it J. Chem. Phys.} {\bf 113}, 4274-4289 (2000).
• G. A. Parker, Mark Keil, Michael A. Morrison and Stefano Crocchianti, Quantum Reactive Scattering in Three Dimensions. Using Tangent-Sphere Coordinates to Smoothly Transform from the Hyperspherical to Jacobi Regions.'' {\it J. Chem. Phys.} {\bf 113}, 957-970 (2000).
• G. A. Parker, S. Crocchianti and M. Keil, Quantum Reactive Scattering for Three Particle Systems using Hyperspherical Coordinates.'' Lagan\a, A. and Riganelli A. Eds., {\it Lecture Notes in Chemistry}, {\bf 75}, 88-100 (2000).
• Antonio Lagan\'a, Alessandro Bolloni, Stefano Crocchianti and Gregory A. Parker, On the Effect of Increasing the Total Angular Momentum on Li+HF Reactivity.'' {\it Chem. Phys. Lett.} {\bf 324}, 466-474 (2000).
• M. A. Morrison, E. G. Layton, and G. A. Parker, Rydberg Electron Interferometry'' {\it Phys. Rev. Lett.} {\bf 84}, 1415-1418 (2000).
• S. S. Iyengar, D. J. Kouri, G. A. Parker and D. K. Hoffman Estimating the Upper and Lower Bounds for the Eigenvalues of any Matrix.'' {\it Theor. Chem. Acc.} {\bf 103}, 507-517 (2000).
• 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).
• R. Gargano, S. Crocchianti, and A. Lagan\'a, The Quantum Threshold Behavior of the $Na+HF$ Reaction.'' {\it J. Chem. Phys.}, {\bf 108}, 6266-6271, (1998).
• 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. A}, {\bf 101}, 6429-6440, (1997).
• 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)
• A. Lagan\a, S. Crocchianti, G. O. Aspuru, R. Gargano and G. A. Parker, Parallel Time Independent Quantum Calculations of Atom Diatom Reactivity.'' {\it Applied Parallel Computing. Computations in Physics} Springer-Verlag, 1041, 361-370 (1996).
• 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).
• 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).
• 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).
• 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).
• Z. Darakjian, E. F. Hayes, G. A. Parker, E. A. Butcher and J. D. Kress, Erratum: Direct and Numerical Calculation of Time Delays for the Reaction $He+H_{2}^{+} \rightleftharpoons HeH^{+}+H$''. {\it J. Chem. Phys.}, {\bf 101}, 9203 (1994).
• 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).
• 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).
• 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).
• 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).
• G. A. Parker and R. T Pack, Quantum Reactive Scattering in Three Dimensions Using Hyperspherical (APH) Coordinates VI. Analytic Basis Method for Surface Functions''. {\it J. Chem. Phys.} {\bf 98}, 6883-6896 (1993).
• G. A. Parker, R. T Pack, and A. Lagan\a, Accurate 3D Quantum Reactive Probabilities of Li+FH''. {\it Chem. Phys. Lett.} {\bf 202}, 75-81 (1993).
• A Lagan\a, R. T Pack, and G. A. Parker, On the Transition State of the $Li+HF$ Reaction,'' {\it Faraday Discuss. Chem. Soc.} {\bf 91}, 386 (1991).
• Z. Darakjian, E. F. Hayes, G. A. Parker, E. A. Butcher and J. D. Kress, Direct Calculation of collisional properties that require energy derivatives of the S matrix: Results for the reaction $He+H_{2}^{+} \rightleftharpoons HeH^{+}+H$''. {\it J. Chem. Phys.} {\bf 95}, 2516-2522 (1991).
• J. D. Kress, Z. Bacic, G. A. Parker and R. T Pack, Quantum Reactive Scattering in Three Dimensions Using Hyperspherical (APH) Coordinates. 5. Comparison Between Two Accurate Potential Energy Surfaces for $H+H_{2}$. Accurate Results for $D+H_{2}$''. {\it J. Phys. Chem.} {\bf 94}, 8055-8058 (1990).
• J. D. Kress, R. T Pack and G. A. Parker, Accurate three-dimensional quantum Scattering Calculations for $F+H_{2} \rightleftharpoons HF+H$ with Total Angular Momentum J=1''. {\it Chem. Phys. Lett.} {\bf 170}, 306-310 (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).
• 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).
• 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).
• J. D. Kress, S. B. Woodruff, G. A. Parker, and R. T Pack, Some Strategies for Enhancing the Performance of the Block Lanczos Method.'' {\it Comp. Phys. Comm.} {\bf 53}, 109-115 (1989).
• J. D. Kress, G. A. Parker, R. T Pack B. J. Archer and W. A. Cook, Comparison of Lanczos and Subspace Iterations
for Hyperspherical Reaction Path Calculations.'' {\it Comp. Phys. Comm.} {\bf 53}, 91-108 (1989).
• G. A. Parker, R. T Pack, A. Lagan\a, B. J. Archer, J. D. Kress, and Z. Bacic, Exact Quantum Results For Reactive Scattering Using Hyperspherical (APH) Coordinates.'', {\it Supercomputer Algorithms for Reactivity, Dynamics and Kinetics of Small Molecules}, Edited by Antonio Lagan\a. {\it Series C: Mathematical and Physical Sciences} (Kluwer and Dordrecht), {\bf 277}, 105-130 (1989).
• R. T Pack and G. A. Parker, Quantum Reactive Scattering in Three Dimensions Using Hyperspherical (APH) Coordinates III. Small Theta Behavior and Corrigenda.'' {\it J. Chem. Phys.} {\bf 90}, 3511-3519 (1989).
• B. J. Archer and G. A. Parker, A Cross Section Code for Diatom Particle Inelastic Scattering.'' {\it J. Comp. Phys.} {\bf 78}, 15-35 (1988).
• A. Lagan\a, R. T Pack and G. A. Parker, A Hyperspherical Approach to Chemical Reactivity of Asymmetric Systems: The $Li+HF$ Reaction.'' {\it Faraday Discuss. Chem. Soc.} {\bf 84}, 409-414 (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).
• 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).
• M. A. Morrison and G. A. Parker, A Beginner's Guide to Rotations in Quantum Mechanics'' {\it Aust. J. Phys.} {\bf 40}, 465-497 (1987).
• G. A. Parker and S. G. Parker, {\it VIVAS } IBM RT PC Software Product Announcement Catalog (1987).
• 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).
• 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).
• G. A. Parker, T. M. Miller, M. Mahgerefteh D. E. Golden, Theory of Angular Correlation Experiments in Electron Scattering Including Fine Structure.'', {\it Phys. Rev.} {\bf A29}, 1770-1784 (1984).
• 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).
• 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).
• G. A. Parker, T. M. Miller and D. E. Golden, Inclusion of Fine and Hyperfine Effects in Electron-Sodium Excitation'', {\it Phys. Rev. A.} {\bf 25}, 588-591 (1982).
• G. A. Parker, VIVAS: The Variable Interval Variable Step Integrator'', {\it Quantum Chemistry Program Exchange} No. {\bf 988} (1982).
• G. A. Parker, VIVS: The Variable Interval Variable Step Integrator'', {\it Quantum Chemistry Program Exchange} No. {\bf 987} (1982).
• L. D. Thomas, M H. Alexander, B. R. Johnson, W. A. Lester, Jr., J. C. Light, K. D. McLenithan, G. A. Parker, M. J. Redmon, T. G. Schmalz, D. Secrest, and R. B. Walker, Comparison of Numerical Methods for Solving the Second-Order Differential Equations of Molecular Scattering Theory'', {\it J. Comp. Phys.} {\bf 41}, 407-426 (1981).
• 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).
• 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, B. R. Johnson and J. C. Light, P-J Hybrid: The Logarithmic Derivative-Variable Interval Variable Step Hybrid Method for the Solution of Coupled Linear Second order Differential Equations'', {\it National Resource Proceedings} No. 5, Vol. II, Algorithms and Computer Codes for Atomic and Molecular Quantum Scattering Theory, p101-104 (1979).
• G. A. Parker, VIVAS-2: Numerical Integrator for Coupled Second Order Differential Equations'', {\it National Energy Software Center} No. 966 (1982).
• G. A. Parker, T. G. Schmalz and J. C. Light, A Variable Interval Variable Step Method for the Solution of Linear Second Order Coupled Differential Equations'', {\it National Resource for Computation in Chemistry Proceedings} No. 5 , Vol. II, Algorithms and Computer Codes for Atomic and Molecular Quantum Scattering Theory, p79-88 (1979).
• G. A. Parker, T. G. Schmalz and J. C. Light, A Variable Interval Variable Step Method for the Solution of Linear Second Order Coupled Differential Equations'', {\it National Resource for Computation in Chemistry Proceedings} No. 5, Vol. I, Algorithms and Computer Codes for Atomic and Molecular Quantum Scattering Theory, p172-198 (1979).
• 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 and R. T Pack, Intermolecular Potential Surfaces from Electron Gas Methods. Angle, Distance and Vibrational Coordinate Dependence of the $Ar-CO$ Interaction'', {\it J. Chem. Phys.} {\bf 69}, 3268-3278 (1978).
• 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).
• 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. C. Nielson, G. A. Parker and R. T Pack, Intermolecular Potential Surfaces From Electron Gas Methods. Angle and Distance Dependence of the A' and A'' $Ar-NO X ^{2}\Pi$ Interactions'', {\it J. Chem. Phys.} {\bf 66}, 1396-1401 (1977).
• G. A. Parker, R. L. Snow and R. T Pack, MOLMOL: Potential Energy Surfaces for the Interaction of Two Linear Molecules'', {\it Quantum Chemistry Program} Exchange No. {\bf 305} (1976).
• G. C. Nielson, G. A. Parker and R. T Pack, van der Waals Interactions of $\Pi$-State Linear Molecules With Atoms. $C_{6}$ For $NO X ^{2}\Pi$ Interactions'', {\it J. Chem. Phys.} {\bf 64}, 2055-2061 (1976).
• 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).
• 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).
• 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).

### FREQUENTLY CITED PUBLICATIONS (more than 100 citations each)

• 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, 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).
• 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).
• 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).
• 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).

### DISTRIBUTED COMPUTER PROGRAMS

• G. A. Parker, R. L. Snow and R. T Pack, {\it MOLMOL: Potential Energy Surfaces for the Interaction of Two Linear Molecules}, Quantum Chemistry Program Exchange No. {\bf 305} (1976).
• G. A. Parker, {\it VIVAS-2: Numerical Integrator for Coupled Second Order Differential Equations}, National Energy Software Center Abstract No. {\bf 966} (1982).
• G. A. Parker, {\it VIVAS: The Variable Interval Variable Step Integrator}, Quantum Chemistry Program Exchange No. {\bf 987} (1982).
• G. A. Parker and S. G. Parker, {\it VIVAS } IBM RT PC Software Product Announcement Catalog (1987).
• G. A. Parker, M. A. Parker, S. G. Parker, and R T Pack, {\it APH3D: The Quantum Reactive Scattering Code} Copyright (1990).
• G. A. Parker, D. K. Hoffman, D. J. Kouri, {DIAG-TIWP: Dirac Delta Function Approach to Matrix Diagonalization} National Institute for Science and Technology, (1995).

### VIDEOS

• E. Gresham, G. A. Parker and N. Shafer-Ray, Time Evolution of
Hydrogen Quantum States in an Electromagnetic Field.''
• D. Burton, M. Grice, R. Kantowski, S. Ryan, and G. A. Parker,
The Audio CD'', {\it Physics Video Project} The University of
Oklahoma 1997.
• K. Slinker and G. A. Parker, Quantum Reactive Scattering''
• R. Kantowski, S. Ryan, and G. A. Parker, Physics Video Clips: Current''

### INVITED LECTURES

• Calculation of Molecule-Molecule Intermolecular Potentials Using Electron-Gas Methods''. Regional Conference: {\it Laser Interactions }. Provo, Utah 1976.
• A Variable Interval Variable Step Method for the Solution of Linear Second Order Coupled Differential Equations (VIVS)''. National Workshop: {\it Algorithms and Computer Codes for Atomic and Molecular Quantum Scattering Theory}. Sponsored by: National Resource for Computation in Chemistry. Chicago, Illinois. June 1979.
• Extraction of Intermolecular Potentials from Experimental Data''. International Conference: {\it New Approaches to Intermolecular Potentials.} Sponsored by: Centre Europeen De Calcul Atomique Et Moleculaire Marseille, France. June 1979.
• A Variable Interval Variable Step Method for the Solution of Linear Second Order Coupled Differential Equations (VIVS)''. National Workshop: {\it Algorithms and Computer Codes for Atomic and Molecular Quantum Scattering Theory.} Sponsored by: National Resource for Computation in Chemistry. Berkeley, California. October 1979.
• The Logarithmic Derivative, Variable-interval Variable-step Hybrid Method for the Solution of Coupled Linear Second Order Differential Equations (VIVAS)''. National Workshop:{\it Algorithms and Computer Codes for Atomic and Molecular Quantum Scattering Theory. } Sponsored by: National Resource for Computation in Chemistry. Berkeley, California. October 1979.
• Sudden Approximations in the Calculation of Transport Properties''. International Conference: {\it Transport Properties of Polyatomic Fluids. }Sponsored by: Statistical Mechanics and Thermodynamics Group of the Chemical Society. London, England. April 1980.
• The Logarithmic Derivative, Variable-interval Variable-step Hybrid Method for the Solution of Coupled Linear Second Order Differential Equations (VIVAS)''. International Conference: {\it Workshop on Numerical Integration of Differential Equations. } Sponsored by: The University of Bielefeld Centre for Interdisciplinary Research. Bielefeld, Germany. April 1980.
• Current Uses of Rotational Decoupling Approximations in Molecular Scattering''. Colloquium: Department of Physics, University of Rolla. Rolla, Missouri. February 1982.
• The State of Reactive Scattering''. National Conference: {\it Atomic and Molecular Interactions.} Sponsored by: Gordon Research Conference. Wolfsboro, New Hampshire. July 1982.
• Reactive Scattering,'' Colloquium: Theoretical Division, Los Alamos, August 1986.
• New Approaches to Reactive Scattering,'' Colloquium: Department of Physics, University of Arkansas, Fayetteville, Arkansas, November 1986.
• Reactive Scattering Using APH Coordinates,'' National Conference: {\it Supercomputers and Chemistry}. Sponsored by: American Chemical Society. Denver, Colorado, April 1987.
• Theory of Chemical Reactions,'' Colloquim: Theoretical Division, Los Alamos, October 1987.
• Reactive Scattering Using APH Coordinates,'' Advanced NATO Research Workshop: {\it Supercomputer Algorithms for Reactivity, Dynamics and Kinetics of Small Molecules} Perugia, Italy, August 1988.
• Quantum Reactive Scattering Using Hyperspherical (APH) Coordinates,'' International Conference: {\it Seventh Conference on Dynamics of Mollecular Collisions.} Assisi, Italy, September 1988.
• Comparison of Lanczos and Subspace Iterations for Reaction Path Calculations,'' National Conference: {\it Workshop on Practical Iterative Methods for Large Scale Computations.} Sponsored by: Minnesota Supercomputer Institute. Minneapolis, Minnesota, October 1988.
• Exact Quantum Results for Reactive Scattering Using Hyperspherical (APH) Coordinates,'' Regional Conference;{\it American Association of Physics Teachers.} Lubbock, Texas, November 1988.
• Hyperspherical Coordinate Approach to Rearrangement Collisions, National Conference: {\it Spring Meeting of the American Physical Society.} Baltimore, Maryland, May 1989.
• Hyperspherical Coordinate Approach to Rearrangement Collisions, National Conference: Spring Meeting of the American Physical Society. April 1991.
• Exact Quantum Results for Reactive Scattering Using Hyperspherical (APH) Coordinates, Colloquium Perugia, Italy. October 1991. Exact Quantum Results for Reactive Scattering Using Hyperspherical (APH) Coordinates, Colloquium Perugia, Italy. March 1992.
• Exact Quantum Results for Reactive Scattering Using Hyperspherical (APH) Coordinates, Invited Speaker Gas Dynamics School, Perugia, Italy. June 1992.
• Exact Quantum Results for Reactive Scattering Using Hyperspherical (APH) Coordinates, Invited Speaker Physics Computing Conference, Albuquerque, New Mexico. May 1993.
• Resonances in Reactive Scattering, Invited Speaker Boston, Mass. August 1994.
• Wavepacket Propagation Techniques for Reactive Scattering, Invited Speaker, Perugia, Italy November 1994. The Theory of Quantum Reactive Scattering, Brigham Young University, Provo, Utah, March 1995.
• Quantum Reactive Scattering Using Time-Independent Wavepackets, Invited Speaker, Columbus, Ohio, April 1995. OHIO
• Distributed Approximating Functionals. Invited Speaker, Chicago, Illinois, June 1995.
• Quantum Reactive Scattering Using APH Coordinates. Invited Speaker, Nottingham, England, September 1995.
• Recent Developments in quantum Reactive Scattering. Invited Speaker, University of North Texas, Denton, Texas, October 1997.Quantum Reactive Scattering, Brigham Young University, 1998.
• Co-Organizer Hyperspherical Coordinate Conference, Seattle Washington, Jan. 1999
• Quantum Reactive Scattering: Using Tangent-Sphere to Smoothly Transform from the Hyperspherical to Jacobi Regions, Invited Speaker: XVI International Conference on Molecular Energy Transfer (COMET XVI), Assisi Italy, June 20-25, 1999. Comet Meeting.
• Quantum Reaction Dynamics, Invited Speaker: Fifth Workshop on Quantum Reactive Scattering, Perugia June 25-27, 1999. Workshop
• Quantum Reactive Scattering, 1$^{st}$ European School of Computational Chemistry: Reaction and Molecular Dynamics, Perugia June 27 - July 4, 1999. European School
• ''Collision Induced Dissociation and Three-Body Recombination'', Molecular Dynamics Conference. Pasadena, California, Jan. 10-13 2001.
• Invited speaker at the Collaborative Computational Project on Molecular Quantum Dynamics (CCP6)
which is a Cold Atom and Molecule Workshop to be held in Durham, England, September 19-22, 2002.
• Colloquium at the University of Colorado, Boulder, Colorado, February 7, 2003

### FUNDING HISTORY

• 2005-2008 DEPSCOR-AFOSR: James S. Shaffer and Gregory A. Parker, ''Three Body Recombination and Photoassociative Ultracold Collisions Studied Using Translational Energy Distributions'', Requesting $537,828.00. • 2004-2007 NSF Physics, Theoretical Physics - Atomic Theory: Gregory A. Parker, Three-Body Recombination and Coherent Control in Ultracold Collisions'' , Awarded$180,006.00.
• 2004-2004 NSF Physics, Theoretical Physics - Atomic Theory: Gregory A. Parker, Three-Body Atomic Recombination in Bose-Einstein Condensates'', Awarded $31,291.00. • 2001-2004 NSF Physics, Theoretical Physics - Atomic Theory: Gregory A. Parker and Russell T Pack, Three-Body Atomic Recombination in Bose-Einstein Condensates'', Awarded$180,014.00.
• 2001-2004 National Science Foundation Physics, Gregory A. Parker and Russell T Pack, Three-Body Atomic Recombination in Bose-Einstein Condensates''. $180,006. • 2001-2004 OU Matching. Gregory A. Parker, Three-Body Atomic Recombination in Bose-Einstein Condensates'',$80,000.
• 1997-2001 National Science Foundation CHE-9710383, Mark Keil and Gregory A. Parker, Vibrationally and Rotationally State-Resolved Differential Cross Sections for Reactive Scattering.'' $393,115. • 1997 University of Oklahoma Research Council, Gregory A. Parker, {\it Reactive Scattering}$6,000.
• 1994-1997 National Science Foundation CHE-9405005, Mark Keil and Gregory A. Parker, State-Resolved Differential Cross Sections for $HF(j)+Ar\rightleftharpoons HF(j^\prime)+Ar$ and $F+H_2\rightleftharpoons HF(\nu^\prime,j^\prime)+H$.'' $333,700. • 1995 International Business Machines, Edward A. Baron, John Cowan, Bruce Mason, Kim Milton, Michael Morrison, Kieran Mullen, Gregory A. Parker, Mike Strauss, Deborah K. Watson, and Ralph A. Wheeler, {\it A High Performance Computer for Physics, Astronomy, and Chemistry Research, Development, and Training},$410,000.
• 1995 University of Oklahoma, Edward A. Baron, John Cowan, Bruce Mason, Kim Milton, Michael Morrison, Kieran Mullen, Gregory A. Parker, Mike Strauss, Deborah K. Watson, and Ralph A. Wheeler, {\it A High Performance Computer for Physics, Astronomy, and Chemistry Research, Development, and Training}, Matching Funds $400,000. • 1995 National Institue for Science and Technology, David K. Hoffman, Donald J. Kouri, and Gregory A. Parker, {\it Proposal for a Parallel Matrix Diagonalization Code},$37,671.
• 1995-1998 National Science Foundation, Undergraduate Education, Course and Curriculum Development Program, Stewart R. Ryan, Pankaj Jain, Ronald Kantowski, and Gregory A. Parker, {\it Production of Short, Animated Audio/Visual Instructional Aids for Physics which Illustrate the Application of Physics to Technology} $34,215. • 1995 University of Oklahoma Equipment Matching Program, Stewart R. Ryan, Pankaj Jain, Ronald Kantowski, and Gregory A. Parker, {\it Production of Short, Animated Audio/Visual Instructional Aids for Physics which Illustrate the Application of Physics to Technology}$6,000.
• 1994-1997 National Science Foundation, Mark Keil and Gregory A. Parker,
{\it State-Resolved Differential Cross Sections for $HF(j)+Ar \to HF(j')+Ar$ and $F+H_2 \to HF(\nu',j')+H$} $342,000. • 1988 MOST Eminent Scholars and Research Equipment Program, Gregory A. Parker,$35,075.
• 1992-1995 NATO Collaborative Research Grant, Antonio Lagan\a and Gregory A. Parker, {\it Parallel Techniques for Calculating Atom Diatom Reactivity and Application to Chemical Lasers, } 204,000 Belgian Francs.
• 1988 University of California Board of Regents, {\it Quantum Reactive Scattering}, $7,700. • 1987-1991 National Science Foundation, Theoretical and Computational Chemistry Program, Gregory A. Parker and Russell T Pack, {\it Quantum Reactive Scattering in Three Dimensions Using Hyperspherical (APH) Coordinates},$255,000.
• 1993 University of Oklahoma Research Council, Gregory A. Parker, {\it Quantum Mechanical Reactive Scattering Using Adiabatically Adjusting Hyperspherical Coordinates.} $5,745. • 1991 University of Oklahoma Research Council, Gregory A. Parker,$5,745.
• 1989 University of Oklahoma Research Council, Gregory A. Parker, $7,000. • 1987 University of Oklahoma Research Council, Gregory A. Parker,$2,860.
• 1985 Associate Western Universities, Gregory A. Parker, {\it Adiabatically Adjusting Hyperspherical Coordinates for Reactive Scattering processes.} $26,400. • 1985-1987 National Science Foundation, David E. Golden, Thomas M. Miller and Gregory A. Parker, {\it Experimental Determination of Scattering Amplitudes and Relative Phases in Electron Impact of Alkali Atoms.}$417,829.
• 1984 Research Council, University of Oklahoma, Gregory A. Parker, {\it Empirical Potentials for Atom Molecule Interactions: Multi-Property Fitting in the Infinite-Order Sudden Approximation.} $5,000. • 1983-1985 National Science Foundation, David E. Golden, Thomas M. Miller and Gregory A. Parker, {\it Experimental Determination of Scattering Amplitudes and Relative Phases in Electron Impact of Alkali Atoms.}$325,288.
• 1983 International Buisness Machines, Gregory A. Parker VIVAS: Variable Interval Variable Step Method for the Solution of Coupled Differential Equations'' $30,000. • 1982 Energy Resource Center, Gregory A. Parker, {\it Quantum wave propagation.}$11,254.
• 1982 Research Corporation, Gregory A. Parker, {\it A New Coupled-Channel Method for Atomic and Molecular Scattering.} $34,000. • 1982 Petroleum Research Fund Adminstered by the American Chemical Society. Gregory A. Parker, {\it Theoretical Determination of the$Ar+CO$Vibrational and Rotational Relaxation Rates.}$10,000.
• 1982 Research Council of the University of Oklahoma, Gregory A. Parker, {\it Determination of Scattering Amplitudes and Relative Phases from Electron Atom Scattering.} $900 • 1982 Junior Faculty Summer Research Fellowship program of the University of Oklahoma, Gregory A. Parker, {\it Sudden Approximations.}$3,500.
• 1981 Research Council of the University of Oklahoma, Gregory A. Parker, {\it A New Coupled-Channel Method for Atomic and Molecular Scattering.} $1,645. • 1981 Undergraduate Research Program of the University of Oklahoma, Gregory A. Parker, {\it Developing Effective Graduate Recruiting Through Undergraduate Research Participation.}$4,000.
• 1980 Research Council of the University of Oklahoma, Gregory A. Parker, {\it A New Coupled-Channel Method for Atomic and Molecular Scattering.} $2,745. • 1980 Junior Faculty Summer Research Fellowship program of the University of Oklahoma, Gregory A. Parker, {\it Molecular Collisions in the Sudden Approximation.}$3,000.

## 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.

• Atomic Physics
• Chemical Physics
• Collision Dynamics
• Molecular Physics
• Mathematical Methods I
• Mathematical Methods II
• Quantum Mechanics I
• Quantum Mechanics II
• Scattering Theory
• Theoretical Mechanics

• Atomic and Molecular Physics
• Chemical Physics
• Physical Mecahnics
• Physics for Engineers I
• Physics for Engineers II
• Physics for Life Sciences I
• Physics for Life Sciences II
• Quantum Mechanics I
• Quantum Mechanics II