This release is available in German.
Spectroscopic techniques are among the most important methods by which scientists can look inside materials. They exploit the interaction of light waves with a given sample.
Now, using X-ray absorption spectroscopy, researchers from Helmholtz-Zentrum Berlin fr Materialien und Energie (HZB) have observed the moving of electric charges from solute to solvent so-called electron transfer. They can even make assertions on the temporal sequence of this process. As one example, they can find out how solute biochemical substances carry out their microscopic functions in their natural environment at room temperature and normal pressure. Until recently, studying such systems by soft X-ray radiation has not been possible. The HZB group led by Emad Aziz reports on this in Nature Chemistry (DOI: 10.1038/NCHEM.768), with their article highlighted in the online pre-issue from 8 August.
The group studied the X-ray absorption spectra of iron ions in both iron chloride and organic compounds such as haemin, the active centre of blood component haemoglobin, and analyzed the hitherto inexplicable negative peak (dip) in the spectra.
In X-ray absorption spectroscopy, monochromatic X-ray light interacts with the sample. When the energy of the incident light exactly matches the energy transfer in the molecule, electrons can be excited out of their ground state into a higher energy state. As they return to their original state, the added energy is released again, as an emission of fluorescent light for example. By recording this fluorescent light, scientists gain an insight into the electron orbital configuration of atoms and molecules.
By making measurements using synchrotron light at the X-ray source BESSY II, Emad Aziz and his colleagues discovered that certain solute substances emit no fluorescent light a
|Contact: Dr. Emad Flear Aziz Bekhit|
Helmholtz Association of German Research Centres