Dissecting X-Ray Raman Resonances Using Four-Wave Mixing

¹ Department of Chemistry, University of California, Irvine, Irvine, CA 92697
² William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P. O. Box 999, Richland, Washington 99352, USA

^a e-mail: mukamel@uci.edu

Abstract

The stimulated x-ray Raman signal has been calculated for the amino acid cysteine using broadband (FWHM ≃14.2eV, 128 as) pulses tuned to the nitrogen K-edge. Peaks correspond to those valence excited states and reveal electronic Frank-Condon overlaps between canonical valence orbitals and relaxed orbitals in the presence of the core hole. The coupling between excited states with valence- and core-holes is further explored using a coherent, wave-vector matched photon echo technique, where it is possible to eliminate stimulated emission and excited-state absorption by taking the waiting time to be longer the lifetime of the core hole (∼ 7:1 fs for nitrogen).