Physics Department News Archive

December 6, 2005

Senior Project Published

Sioux Falls - For the third time since August, work done by an Augustana College physics student has been published in Physical Review. This time, the senior research project of 2005 Augustana College graduate Kelsie Betsch has been published as part of a larger study appearing in the December issue of Physical Review A. The article, "Closed-Loop Control of Intense-Field Ionization of S8", describes how intense, short pulses of laser light may be used to selectively fragment sulfur clusters. Betsch contributed to the project by using a statistical analysis technique, called principal control analysis (PCA), to determine which parts of the laser pulse contributed to controlling the fragmentation and which parts were superfluous.

"Kelsie's PCA work helped bring our results together and strengthened the paper", says Professor Robert R. Jones of the University of Virginia. By learning what parts of the laser pulse are crucial to the control process, it may be possible to reach a more general understanding of how the control works. Controlling fragmentation of molecules is a necessary step in using lasers to control chemical reactions.

Betsch, a 2004 Goldwater scholar, earned physics and chemistry degrees from Augustana last spring. She is from New Ulm, MN, and is the daughter of Leigh and Patricia Betsch. Her work was completed as part of the requirements of the physics advanced laboratory class. In this course, each senior physics major completes an independent research project. The experiment itself was conducted at the University of Virginia.

Funding for the experiment was provided by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy. The Physical Review is a journal of the American Physical Society, and Physical Review A is the section of this journal dedicated to atomic, molecular, and optical physics research. Physical Review is stringently peer-reviewed and is generally regarded as the most prestigious physics-only journal in the world.


  1. 1. E. Wells, K.J. Betsch, C.W.S. Conover, Merrick J. DeWitt, D. Pinkham, and R.R. Jones, Phys. Rev. A 72, 063406 (2005) .

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