Abstract

The ability to “watch” ultrafast quantum motions of molecular electrons and nuclei can help us gain new insights on elementary events. This is expected to lead to new physical and chemical processes created through the control and manipulation of atoms and electrons in molecules on ultrafast time scales. Novel beam sources like x-ray free electron lasers (XFELs) have unprecedented brilliance, tunability, and time resolution, offering new capabilities for probing fundamental coherence phenomena in molecules. In this talk, I will discuss recent experimental advances in ultrafast x-ray scattering where we exploit ultrashort hard x-ray pulses of the Linac Coherent Light Source (LCLS) to study ultrafast structural dynamics in free molecules, including direct measurement of the vibrational coherence and dephasing in an excited-state polyatomic molecule, and observation of nearly-instant changes in electron density upon photoexcitation. I will then discuss future opportunities such as capturing vibronic coherences at conical intersections and real-time monitoring of light-induced molecular chirality.