X-rayed transfer

X-ray absorption spectroscopy can be used to observe electron transfer, the movement of electric charges from solute to solvent, according to German researchers. The group at the Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) used EXAFS of iron ions in both iron chloride and organic compounds such as hemin, the active center of hemoglobin to explain the hitherto inexplicable negative peak in its spectra. Measurements made using synchrotron light from the BESSY II X-ray source, allowed the team to show that certain solutes emit no fluorescent light after excitation because the radiationless return to the ground state takes place through a so-called "dark channel". The revelation could explain the contribution of solvent to the function of biochemical systems such as proteins.