报告题目：Applications of Synchrotron Techniques in Geochemistry

报 告 人：Glenn Waychunas（Senior Scientist, Lawrence Berkeley National Laboratory, Earth Sciences Division）

时　　间：2013年5月23日下午1：00

地　　点：张江办公楼101会议室

摘要

Early synchrotron research in geochemistry focused on the characterization of minor elements in minerals and in glasses or melts inaccessible by other methods, mainly using　the (then) new EXAFS and XANES techniques.　With the opportunities opened by very bright sources, grazing incidence methods soon were being used to examine mineral-water interface and metal toxin sorption at a new level of detail.　X-ray microprobes and related spectromicroscopy were also being developed, affording unprecedented chemical-imaging capabilities.　Next the structures and reactivity of natural composition nanoparticles began to be explored, both via spectroscopy and scattering, yielding some surprises.　Today the full spectrum of synchrotron methodology is being used in most areas of geochemical research, and opportunities with XFEL sources are being explored.　In this talk I touch on these various areas and briefly describe some of the lines of research currently under way at LBNL/UC Berkeley, including carbonate nucleation processes (for geological carbon sequestration) examined via GISAXS, fast electron transfer in iron oxide nanoparticles (reductive dissolution) using laser pump/x-ray probe methods, molecular scale formation processes for acid-mine drainage (AMD) using QEXAFS, and nanoprobe analyses of “coatings” in sediments that affect geochemical reactivity.