Using X-ray Emission Spectroscopy to Study How Plants Split Water

X-ray emission spectroscopy provides unique insights on the electronic structure and ligand environment of metal coordination compounds and active centers in metalloproteins. Recent advances in hard X-ray emission spectroscopy instruUation at SSRL and LCLS will be presented. In particular we will describe the new scanning spectrometer at SSRL beamline 6-2 and the new dispersive X-ray emission spectrometer based on the Von Hamos geometry, mainly developed for LCLS. We will then focus on how XES is used to study the photosynthetic splitting of water occurring in the Mn containing catalytic center of the Photosytem II protein. Results from our recent LCLS experiments will be discussed.