Speaker
Description
HERFD and RIXS have been a mainstay of advanced high-resolution spectroscopy particularly with HERFD-XAS. Much higher resolution spectra are obtainable than in X-ray absorption, with interesting challenging resolution functions. Two primary axes of incident and emission energy, are transformable to the energy-loss axis by rotation. Major challenges have included the difficulty of any theoretical understanding of HERFD spectra. Another major challenge is the difficulty of energy calibration, or the non-portability of calibration of incident and emission energy. Our recent experiments have moved into the Tender Regime, where detector, dosimetry, and calibration challenges become more serious. The understanding that HERFD theory and HERFD-XAS is not directly fittable by XAS theory. We present theory which can explain HERFD spectra. We introduce XR-HERFD as a new insightful experimental setup which requires this more advanced theory, to make discoveries of new physical processes in materials spectra, and to understand where these processes come from. We present Hidden Satellites in Manganese to show how advanced theory and experiment can lead to new discoveries.
NTT Tran etal., A New Satellite of Manganese revealed by Extended-Range High-Energy-Resolution Fluorescence Detection JSR30(2023)605-612
D Sier etal., High Accuracy, High-Accuracy High-Resolution Measurements of Fluorescence in Manganese using Extended-Range High-Energy-Resolution Fluorescence Detection. J Applied Cryst58(2025)42-59 doi10.1107/S1600576724010574
R Rijal etal., Hyper-resolution in X-ray Emission Spectroscopy: Integrating XR-HERFD and Multiple Crystal Spectrometry with Advanced Binary Data Splicing JSR(2025)32(4)994-1009
JW Dean etal., Ab Initio Manganese Kα and Kβ Energy Eigenvalues, Shake-Off Probabilities, Auger Rates, with Convergence Tests, Molecules 29(2024)4199–1–26
JA Stephens etal., Discovery of an Energy-Dependent Many-Body Process in the Kβ Spectrum of Manganese Metal using Extended-Range High-Energy-Resolution Fluorescence Detection with Advanced Structural Insights from Principal Component Analysis. IUCrJ12(2025)548-562
R Rijal etal., Discovering Hidden Satellites in Mn Kα Spectra using High-Accuracy Fluorescence, with Principal Component Analysis to reveal Evolution of new Processes, Nature Structure Reports(2026)