Dr. Sandra Quintanilla, Associate Professor
 
 
  Department of Physics
P.O. Box 311427
Denton, Texas  76203-1427		 (940) 565-4739
Science Research Building, Room 228
squintanilla@unt.edu
 
   
Education:  

Ph.D., Royal Holloway and Bedford New College, University of London, 1986
Atomic Physics, Scattering

 

Research:   Dr. Quintanilla is an atomic theorist.  In particular she studies positron collision, (E-2e) collisions, and photon interactions.
 
Publications:    
  1. "The Scattering of Low-Energy S-Wave Electrons by Positronium," S.J. Ward, J.W. Humberston and Mr.C. McDowell, J. Phys. B: At. Mol. Phys. 18, L525-L530 (1985).
 
  2. "The Photodetachment of the Negative Ion of Positronium (Ps-)," S.J. Ward, J.W. Humberston and M.R.C. McDowell, Europhys. Lett. 1, 167-171 (1986).
 
  3. "Elastic Scattering of Electrons (or Positrons) from Positronium and the Photodetachment of the Positronium Negative Ion," S.J. Ward, J.W. Humberston and M.R.C. McDowell, J. Phys. B: At. Mol. Phys. 20, 127-149 (1987).
 
  4. "Close-coupling Approach to Positron Scattering from Potassium," S.J. Ward, M. Horbatsch, R.P. McEachran, and A.D. Stauffer, J. Phys. B: At. Mol. Opt. Phys. 21, L611-L616 (1988).
 
  5. "Close-Coupling Approach to Positron Scattering for Lithium, Sodium and Potassium," S.J. Ward, M. Horbatsch, R.P. McEachran and A.D. Stauffer, J. Phys. B: At. Mol. Opt. Phys. 22, 1845-1861 (1989).
 
  6. "Close-Coupling Approach to Positron Scattering from Potassium," S.J. Ward, M. Horbatsch, R.P. McEachran and A.D. Stauffer, J. Phys. B: At. Mol. Opt. Phys. 21, L611-616 (1988).
 
  7. "Resonances in Low-Energy Positron Scattering from Li, Na and K," S.J. Ward, M. Horbatsch, R.P. McEachran and A.D. Stauffer, J. Phys. B: At. Mol. Opt. Phys. 22, 3763-3744 (1989).
 
  8. "A Variational Principle for Time-Dependent Interactions," S.J. Ward and J.H. Macek, Phys. Rev. A 43, 155-171 (1991).
 
  9. "Recent Developments in the Theory of Positron-Hydrogen Collisions," S.J. Ward, Proceedings of Invited Talks of the XVIII International Conference on the Physics of Electronic and Atomic Collisions, AIP Conference Proceedings 295, edited by T. Anderson, B. Fastrup, F. Folkmann, H. Knudsen and N. Andersen (AIP Press, New York, 1993), pp. 466-477.
 
  10. "Wave Functions for Continuum States of Charged Fragments," S.J. Ward and J.H. Macek, Phys. Rev. A 49, 1049-1056 (1994).
 .
  11. "Positronium Formation by Electronic Capture from Hydrogenic Ions," S.J. Ward and J.H. Macek, Hyperfine Interact. 89, 477-482 (1994).
 
  12. "Recent Development in the Theory of Fast Positron-Atom Collisions," S.J. Ward, Nucl Instr. and Meth. in Phys. Res. B 99, 368-371 (1995).
 
  13. "The Hidden Crossing Method Applied to Poistronium Formation," S.J. Ward, J.H. Macek and S. Yu. Ovchinnikov, in Proceedings of the Fourteenth International Conference on the Application of Accelerators in Research and Industry, AIP Conference Proceedings 392, edited by J.L. Duggan and I.L. Morgan, (AIP Press, Woodbury, New York, 1997), pp. 469-472.
 
  14. "Hidden Crossing Method Applied to Positronium Formation," S.J. Ward, J.H. Macek and S.Yu. Ovchinnikov, Nucl. Instr. and Meth. in Phys. Res. B 143, 175-183 (1998).
 
  15. "Application of the Hidden Crossing Method to Positronium Formation," S.J. Ward, J.H. Macek, and S. Yu. Ovchinnikov, Phys. Rev. A 59, 4418-4427 (1999).
 
  16. "Effective Range Analysis of Positron-Hydrogen Collisions," S.J. Ward and J.H. Macek, Phys. Rev. A 62, 52715-1 -52715-15 (2000).
 
  17. "Positronium Formation in Low-Energy Positron Collisions with One-and Two-Electron Atoms," S.J. Ward, Comments on Modern Physics 2, D245-D261 (2002).
 
  18. "The Effect of the Polarization Potential on Low-Energy Atomic Processes," S.J. Ward, J.C. Hunnell and J.H. Macek, Nucl. Instr. and Meth. in Phys. Res. B 192, 54-62 (2002).
 
  19. "Application of the Hyperspherical Hidden Crossing Method to Positron-Lithium Collisions," S.J. Ward and J. Shertzer, Phys. Rev. A 68, 032720-1 -- 032720-8 (2003).
 
  20. "Effect of the Core Polarization Term on Ps Formation in Low-Energy e+ -Li Collisions," S.J Ward and J. Shertzer, Nucl. Instr. and Meth. in Phys. Res. B 221, 206-209, 2004.
 
  21. "Effect of Polarization on Photodetachment Thresholds," J. Standtröm, G. Haeffler, I. Kiyan, U. Berzinsh, D. Hanstrop, D.J. Pegg, J. C. Hunnell and S.J. Ward, Phys. Rev. A 70, 052707-1 -- 052707-11, 2004.
 
  22. "Positronium Formation Cross Section for Positron-Lithium Collisions," S.J. Ward and J. Shertzer, Nucl. Instr. and Meth. in Phys. Res. B 241, 257-261, 2005.
 
  23. "Binding Energy and Structure of e+Li and e-Li Using a Parametric Model Potential," J. Shertzer and S.J. Ward, Phys. Rev. A. 73, 022504-1 -- 022504-4 (2006).
 
  24. "Optimizing the Paths for Including the Correction Term to the Hyperspherical Hidden Crossing Method:  Application to Ps formation in e+-LI collisions," S.J. Ward, J. Shertzer, S. Yu
 
  25. "The Scattering of Low-Energy Electrons by Positronium," S.J. Ward, J.W. Humberston and M.R.C. McDowell, Contributed paper in Proceedings of the Third International Workshop on Positron (Electron)-Gas Scattering, edited by W.E. Kauppila, T.S. Stein and J. Wadehra (World Scientific, Singapore, 1986) pp. 307-309.
 
  26. "Theoretical Studies of Low-Energy Positron-Alkali Atom Scattering," S.J. Ward, M. Horbatsch, R.P. McEachran and A.D. Stauffer, Invited Paper in Atomic Physics with Positrons, edited by J.W. Humberston and E.A.G. Armour, (NATO ASI Series B: Physics Vol. 169, Plenum Press, New York, 1988), pp. 265-276.
 
  27. "Theoretical Calculations of Positron Collisions with Atoms," A.D. Stauffer, K. Bartschat, R.I. Campeanu, M. Horbatsch, R.P. McEachran, L.A. Parcell and S.J. Ward, Proceedings of Invited Talks of the XVI International Conference and Atomic Collisions, AIP Conference Proceedings 205, edited by A. Dalgarno, R.S. Freund, P.M. Koch, M.S. Lubell and T.B. Lucatoro.
 
  28. "Resonances in Positron-Alkali Close-Coupling Calculations," M. Horbatsch, S.J. Ward, R.Pl. McEachran and A.D. Stauffer, Contributed Paper in Proceedings on the Workshop on Annihilation in Gases and Galaxies, NASA Conference Publication 3058, edited by R.J. Drachman, (NASA, 1990) pp. 261-262.
 
  29. "Positron-Alkali Atom Scattering," R.P. McEachran, M. Horbatsch, A.D. Stauffer and S.J. Ward, Invited Paper in Proceedings on the Workshop on Annihilation in Gases and Galaxies, NASA Conference Publication 3058, edited by R.J. Drachman, (NASA, 1990) pp. 1-11.
 
  30. "Single and Double Photoionization of Helium," S.J. Ward and J.H. Macek, Bull. Am. Phys. Soc. 39, 2013 (1994).
 
  31. "The Hidden Crossing Method Applied to Positronium Formation," S.J. Ward, J.H. Macek and S. Yu. Ovchinnikov, Bull. Am. Phys. Soc. 41, 1093 (1996).
 
  32. "The Hidden Crossing Method Applied to Positronium Formation," S.J. Ward, J.H. Macek and S. Yu Ovchinnikov, Bull. Am. Phys. Soc. 42, 958 (1997).
 
  33. "Anti-Capture to the Continuum via a Double Collision Mechanism in (e, 2e) Collisions," S.J. Ward, E.G. Roth, B.N. Guo, D.E. Golden and D.W. Mueller. Am. Phys.Soc. 42, 959 (1997).
 
  34. "Hidden Crossing Theory Applied to Ps-formation in Positron-Hydrogen Collisions," S.J. Ward, J.H. Macek and S. Yu Ovchinnikov, Bull. Am. Phys. Soc. 43, 1307 (1998).
  35. "Analysis of Positron-Hydrogen Collisions Using an Effective Range Theory," S.J. Ward and J.H. Macek, Bull. Am. Phys. Soc. 44, 1247 (1999).
 
  36. "Virtual State of the Positronium-Proton System," S.J. Ward and J.H. Macek, Bull. Am. Phys. Soc. 45, 87 (2000).
 
  37. "Effective Range Theory Analysis of Positron-Helium Collisions," S.J. Ward, Bull. Am. Phys. Soc. 46, 69 (2001).
 
  38. "Hyperspherical Hidden Crossing Calculation of Positron-Lithium Collisions," S.J. Ward and J. Shertzer, Bull. Am. Phys. Soc. 47, 113 (2002).
 
  39. "Photodetachment of Alkali Negative Ions," J.C. Hunnell, S.J. Ward, J Sandström, D. Hanstorm and D.J. Pegg, Bull. Am. Phys. Soc. 47, 29 (2002).
 
  40. "The Application of the Hyperspherical Hidden Crossing Method to Positronium Formation in Positron-Lithium Scattering," S. Ward and J. Shertzer, Bull. Am. Phys. Soc. 48, 49 (2003).
 
  41. "Higher Order Corrections to Wannier Threshold Law for Positron Scattering," James Sternberg, S.J. Ward, J.H. Macek, and J. Shertzer, Bull. Am. Phys. Soc. 49, no. 3, p. 52 (2004).
 
  42. "Hyperspherical Hidden Crossing Calculation of Ps Formation Cross Section for Low-Energy e+-Li Collisions," Janine Shertzer and Sandra Ward, Bull. Am. Phys. Soc. 50, no. 3, p. 123 (2005).
 
  43. "The Photodetachment of Ps- and Low-Energy e+-H Collisions," S.J. Ward, accepted for publication in "Proceedings of the Temkin-Drachman Symposium," held on Nov. 18, 2005 at NASA/Goddard Space Flight Center, edited by A.K. Bhatia.
 
  44. "Binding Energy of e+Li using the Peach Model Potential," Janine Shertzer and Sandra Ward, Bull. Am. Phys. Soc. 51, no. 3, p. 103 (2006).
 
  45. "lThe Photodetachement of Ps- and Low-Energy e+-H Collisions," S. J. Ward, in "NASA GSFC Science Symposium on Atomic and Molecular Physics, NASA/CP-2006-214146," edited by A. K. Bhatia, National Aeronautics and Space Administrations, Goddard Space Flight Center, p. 137-143..
 
  46. "Near Threshold Positron Impact Ionization of Hydrogen," Krista Jansen, S. J. Ward, J. Shertzer and J. H. Macek Bull. Am. Phys. Soc. 52, no. 7, p. 50 (2007).
 
     

For more Information:

You may e-mail Dr. Quintanilla at squintanilla@unt.edu

Or send mail to

Department of Physics
P.O. Box 311427
University of North Texas Denton, Texas 76203-1427

(940) 565-2626

Last Updated 25-Feb-2008