Energy-DependentEvolution of Novel Relativistic QuantumMany-Body Hidden Satellites in Zinc X-Ray Emission Revealedby XR-HERFD

Abstract We present the first experimental observation of long-unresolved many-body satellite features within the Kα1,2 X-ray emission spectra of zinc (Zn) with statistical significance exceeding 50 σse per data point. These novel structures, “Hidden Satellites”, were discovered using an extended-range high-energy-resolution fluorescence detection (XR-HERFD) technique at the I20-Scanning beamline of the Diamond Light Source in UK. The measurements employed a 14-crystal analyzer array specifically designed to enhance both energy resolution and statistical accuracy. The Hidden Satellites are revealed within the main Kα1,2 emission peak and exhibit a systematic evolution with increasing incident photon energy. Principal component analysis (PCA) was employed to independently isolate these novel features and trace the evolution of these structures. Remarkably, these hidden features contribute 15% to 20% of the total emission intensity, directly challenging the long-standing assumption that the many-body reduction factor (S02) is constant. We observe that S02 exhibits a clear energy dependence, changing by over 20% over the observed energy range, with broad implications for the analysis and interpretation of X-ray absorption and emission spectra in transition metals and their compounds. Overall, it provides a new foundation for interpreting X-ray spectroscopy, influencing thousands of studies across chemistry, physics, and biology. Despite zinc metal being considered a “simple” d10 metal, the complexity of structure, asymmetry and evolution of these new processes is dramatic and points to a rich new area of inquiry.