Time-resolved XUV and X-ray Photoelectron Spectroscopy of Gas-phase Molecules

Kansas State University, Manhattan KS

Investigators

Abstract

With support from the Atomic, Molecular and Optical Experimental Physics Program in the Division of Physics, and co-funding from Office of Strategic Initiatives in the Directorate for Mathematical and Physical Sciences, and the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Daniel Rolles of Kansas State University intends to perform photoelectron spectroscopy of gas-phase molecules. The advent of high-repetition-rate light sources from the extreme ultraviolet to the X-ray regime is a game-changing opportunity for the fields of ultrafast atomic and molecular physics, and gas-phase photochemistry, since they enable experimental studies to be performed in a time-resolved manner with femtosecond resolution. The results will have a profound impact on our understanding of chemical reaction mechanisms and of the control of chemical reaction dynamics. Being able to record “molecular movies” of benchmark photochemical reactions will allow for a more direct comparison to quantum chemistry calculations and therefore not only result in a better understanding of the underlying reaction mechanism, but ultimately also help to develop and optimize schemes for controlling the dynamics and outcomes of such reactions. Students and post-doctoral researchers will greatly benefit from participating in the project. They will become familiar with many tools and techniques of ultrafast laser science while experiencing a wide variety of research environments ranging from a state-of-the-art laser laboratory at a university to large-scale user facilities such as free-electron lasers and synchrotron light sources. These opportunities will prepare them for their future career either in academic or high-tech industrial research. The research of this project also has significant technological implications with potential benefits to society, e.g., through the development of novel materials for light harvesting or through a better understanding and control of the environmental impact of certain chemicals in the atmosphere. This project focuses specifically on imaging nuclear and electronic dynamics during photochemical reactions by means of time-resolved photoelectron spectroscopy with X-ray free-electron lasers and high-order harmonic generation sources. The aim of these experiments is to study exemplary reactions in gas-phase molecules with the goal of clarifying their reaction mechanisms and pathways. Light-induced reactions in gas-phase molecules play a major role, e.g., in atmospheric chemistry and can also serve as prototypes for (bio-) chemical processes occurring, for instance, during the biosynthesis of vitamin D and for organic molecular switches. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.