Soft X-Ray Spectroscopy And Imaging Of Interfacial Chemistry In Environmental Specimens

Interfaces between minerals and water, and minerals and microbes, are chemically complex and traditionally have been considered beyond the capabilities of surface science techniques, except for model systems under controlled laboratory conditions. We report on some advances in soft x-ray spectroscopy and imaging that make it possible to extract meaningful chemical information about interfaces of specimens that have complex histories, involving environmental exposure. These measurements utilize x-ray absorption spectroscopy, in combination with spatial resolution, in a technique called x-ray spectromicroscopy. Examples are drawn from attempts at Mn and Fe speciation of biologically produced minerals, bio-corrosion deposits and clays