Journal Article RIXS Research Support, Non-U.S. Gov't X-ray optics C and O K-edge spectra FEL IRIXS beamline Petra III, DESY Research Support, U.S. Gov't, Non-P.H.S. Silicon Strehl ratio X-ray FEL X-ray emission spectroscopy X-ray free-electron laser Z4152N8IUI beamlines data acquisition instrumentation diced crystal analyzers extreme conditions high energy-resolution high pressure high-resolution monochromators laser heating lithium-ion battery electrolyte monochromator crystal multi-photon counting non-resonant inelastic X-ray scattering non-traditional crystal materials nuclear resonant inelastic scattering protein crystallography