STRONG RESONANCES IN CORE-LEVEL PHOTOEMISSION

We predict very strong peak enhancements in core-level photoemission at the resonance with a deeper core-level absorption. This allows a straightforward interpretation of core-level spectroscopy in two ways: (a) photoemission peaks can be resolved in resonance with different x-ray absorption peaks, and (b) x-ray absorption peaks can be resolved using partial electron yield at constant binding energy. This can be used to study covalency effects in transition-metal, rare-earth, and actinide compounds. An example is given for nickel metal using a cluster calculation including multiplet structure