Electronic Population Transfer via Impulsive Stimulated X-Ray Raman Scattering with Attosecond Soft-X-Ray Pulses
Jordan T. O’Neal, Elio G. Champenois, Soléne Oberli, Razib Obaid, André Al Haddad, Jonathan C. T. Barnard, N. Berrah, Ryan Coffee, Joseph Duris, Gediminas Galinis, Douglas Garratt, James M. Glownia, Daniel J. Haxton, Phay J. Ho, Siqi Li, Xiang Li, James MacArthur, J. P. Marangos, Adi Natan, Niranjan Shivaram, Daniel Slaughter, Peter Walter, Scott Wandel, Linda Young, Christoph Bostedt, P. H. Bucksbaum, Antonio Picón, Agostino Marinelli, James Cryan
Abstract
Free-electron lasers provide a source of x-ray pulses short enough and intense enough to drive nonlinearities in molecular systems. Impulsive interactions driven by these x-ray pulses provide a way to create and probe valence electron motions with high temporal and spatial resolution. Observing these electronic motions is crucial to understand the role of electronic coherence in chemical processes. A simple nonlinear technique for probing electronic motion, impulsive stimulated x-ray Raman scattering (ISXRS), involves a single impulsive interaction to produce a coherent superposition of electronic states. We demonstrate electronic population transfer via ISXRS using broad bandwidth (5.5 eV full width at half maximum) attosecond x-ray pulses produced by the Linac Coherent Light Source. The impulsive excitation is resonantly enhanced by the oxygen 1s→2π^{*} resonance of nitric oxide (NO), and excited state neutral molecules are probed with a time-delayed UV laser pulse.