HIGH-RESOLUTION X-RAY-FLUORESCENCE AND EXCITATION SPECTROSCOPY OF METALLOPROTEINS

A spectrograph has been developed with sufficient efficiency to make h igh-resolution fluorescence experiments on metalloproteins possible. T he resolution of this spectrometer can reach 0.45 eV at 7.1 keV emissi on energy. The focus images of this multiple curved-crystal array spec trometer are presented. The chemical sensitivity of K beta emission sp ectra can be used to identify chemical states, and the spin-polarized near-edge structure provides a new measure of the spin density. The hi gh-resolution fluorescence metalloprotein studies should become routin e with third-generation synchrotron facilities, and the strength of bo th site and spin selectivity should complement the structural informat ion from other spectroscopies.