Dr. Vinod Kumarappan
Kansas State University, Department of Physics
Alignment and Orientation of Molecules with Lasers: A Quest for the Molecular Frame
102 Cardwell Hall
September 16, 2013
4:30 p.m.
The interactions of molecules with each other and with external fields depend on their relative orientation, but often this aspect is obscured by thermal rotational motion. In this Colloquium I will describe our efforts to control the orientation of gas-phase molecules using strong non-resonant laser fields with the goal of making measurements in the molecular frame. These include one-dimensional alignment and orientation of linear molecules and three-dimensional alignment of asymmetric top molecules. I will also discuss how the angle dependence of photo-induced processes can be obtained using pump-probe measurements from a rotational wave-packet. These techniques provide us with access to molecular frame information that is, especially for asymmetric tops, currently unattainable by any other means. As examples, I will describe how we extract
angle-dependent photo-ionization rates in nitrogen and ethylene from high harmonic generation and ion yield measurements, respectively.
