Bryn Mawr Professor Will Give Talk on Probing Molecular Structure and Dynamics Friday

Elizabeth F. McCormack, associate professor of physics at Bryn Mawr College, will speak on “Probing Molecular Structure and Dynamics Using Resonant, Four-Wave Mixing” noon Friday in Hugel Science Center room 100.

The lecture is sponsored by the Physics Club, which will provide free pizza and drinks.

McCormack’s research interests include using techniques in nonlinear optical laser spectroscopy to study fundamental characteristics and excited state decay dynamics of atoms and small molecules.

She participated in development of an integrated science curriculum for a new science college for women, Effat College, in Saudi Arabia. She directed the Science as Exploration Institute in 2001, bringing regional faculty together with pre-college teachers from the Philadelphia School District to share perspectives on how to enhance science and mathematics education throughout the curriculum by using “minds-on,” inquiry-based teaching and learning techniques

McCormack received her bachelor’s degree from Wellesley College in 1983 and her Ph.D. in physics from Yale University in 1989. She then joined the Laser Photophysics and Photochemistry program at Argonne National Laboratory as a Postdoctoral Research Associate. In 1990 she was awarded an Alexander Hollaender Distinguished Postdoctoral Fellowship. The next year she accepted a permanent staff position in the Laser Photophysics and Photochemistry program, and in 1993 she was promoted to the position of physicist. In 1995 she joined the faculty at Bryn Mawr College.

McCormack is a member of the American Physical Society, the Association for Women in Science, and the American Association for Physics Teachers. She is a Faculty 21 member of Project Kaleidoscope.

The talk description: Nonlinear optical techniques continue to be developed and used to investigate atomic and molecular systems difficult to study using conventional spectroscopic techniques. Resonant four-wave mixing is one example and it provides the basis of laser-induced grating spectroscopy. Useful in both the frequency and time domains, it has been used most recently to probe the structure and dynamics of fundamental molecules in the gas phase. We present a combined theoretical and experimental study of the effects of laser polarization on optical coherences produced in two-color, resonant four-wave mixing (TC-RFWM). Good agreement is found between the predictions of a time-dependent model and measurements of beat structures due to coherent excitation of molecular hyperfine states in time-resolved TC-RFWM in nitric oxide (NO). Measured hyperfine energy intervals for the ground and excited A state of NO are reported. The results reveal an unexpected interaction between nuclear spin and vibrational motion in the NO molecule. The results also demonstrate the effectiveness of TC-RFWM for performing state-selective quantum-beat spectroscopy, where the induced optical coherences can be controlled by suitably choosing three experimental features: laser pulse time-ordering, excitation scheme, and laser polarization configuration.

Previous Physics Club talks in 2003-04:

• Craig Markwardt, Laboratory for High Energy Astrophysics at NASA’s Goddard Space Flight Center: “Caught in the Act:What Accreting Millisecond Pulsars Tell Us about Galactic Ecology”
• Kim Coble, National Science Foundation Astronomy and Astrophysics Postdoctoral Fellow at the University of Chicago and an instructor at Adler Planetarium: “Mapping the Universe from Antarctica”
• Brett Fadem, faculty fellow in physics at Colby College: “Nuclear Matter under Extreme Conditions”
• David Helfand, chair of the department of astronomy and astrophysics at Columbia University: “The Universal Timekeeper” and “The Cooling of Neutron Stars”
• New York University physicist Alan Sokal: “Are the Science Wars Over?”
• Suzanne Amador Kane, associate professor and chair of physics and astronomy at Haverford College: “Good Things in Small Packages: Biologically-inspired Nanostructures”
• Michael Shara, curator at the American Museum of Natural History’s Department of Astrophysics: “Relativity for the Millions: Einstein”
• Elliott Horch, assistant professor of physics at University of Massachusetts-Dartmouth: “New Opportunities for Astrophysics with Binary Stars”
• Physics majors Cavan Stone ’05 (Shirley, Mass.) and Ibrahima Bah ’06 (Bronx, N.Y), and electrical and computer engineering major Simon Mushi ’06 (Gaborone, Botswana): Researchpalooza