[phas-dept] Apr. 27 (Thursday) 4 PM - Physics and Astronomy Colloquium

[Heungman Park]

Spring 2017 Colloquium

Department of Physics & Astronomy

April 27, Thursday, 4-5 PM in Science Building 127

(coffee and cookies will be served at 3:50 PM)

Atomic Molecular Optical (AMO) Physics

Vortices in atomic collisions
Dr. Sandra Quintanilla

University of North Texas

[https://lh4.googleusercontent.com/Y0IS9VBLxiqWR5Y9eh3Yb3n5UPnH9gb5GpVMKuYvJeBaZTMPP1-11vG9xaDaRtMH9bEU10FYmMnG5Fbnlq3RSyp4s84tE3-rfBVpvZllVxjnk5supjHU_hKC4Xp2xxjPNs_E4Z9X]

Dr. Sandra Ward Quintanilla earned B.Sc. with 1st class honours in 1983 in Physics at Royal Holloway College, University of London, UK. She earned her Ph.D. in 1986 in Atomic Physics at the Royal Holloway & Bedford New College, University of London. The title of her Ph. D. thesis is “A Theoretical study of Elastic Electron Positronium Scattering and Photo-absorption by the Positronium Negative Ion". She worked as a post-doc at York University, Toronto, Canada and at the University of Tennessee, Knoxville, before coming to the University of North Texas as an assistant professor in 1991. She was on Faculty Development Leave for the academic year where she divided her time between the University of Tennesse, Knoxville, and the Institute of Theoretical Atomic and Molecular Physics at the Harvard-Smithsonian Center for Astrophysics. In 1997, Dr. Quintanilla was promoted to associate professor and in 2007 as full professor. Dr. Quintanilla’s research is in theoretical atomic physics. http://physics.unt.edu/people/sandra-quintanilla-phd


Abstract: Vortices are of interest in many areas of physics such as fluid dynamics, astrophysics, condensed matter, and nonlinear dynamics. Vortices have been studied for macroscopic multiparticle systems, such as Bose-Einstein condensates. It is interesting that a zero in a complex function is related to the physical process of the transfer of angular momentum. Recently, a deep minimum in experimental measurements in the triply differential cross section for electron-impact ionization of helium has been interpreted in terms of a vortex. We have theoretically obtained vortices in the atomic process of inner-shell ionization of carbon by electron impact, electron-impact ionization of atomic hydrogen and positronium formation of positron-hydrogen collisions. This is exciting since it had been predicted that deep minima (exact zeros) in the triply differential cross section could not be obtained for ionization of hydrogen by electron impact.

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