Author:
Anderson Ian M.,Bentley J.
Abstract
The scope of microanalysis encompasses a variety of the charactersitics of a small volume of material, from its composition to its electronic structure. One such characteristic is the local environment of the elements in the volume, including the identity and coordination of the near-neighbors of each element. For multisublattice crystals, this level of the chemistry is characterized by the site-occupancies of the elements composing the crystal. Atom-location by channeling-enhanced microanalvsis (ALCHEMI) is a powerful technique for the experimental measurement of tiiese site-occupancies. Following its introduction, ALCHEMI enjoyed initial successes for the study of cation distributions in oxide minerals. However, the technique was prone to large systematic errors for analyses that required soft (≤ 4 keV) X rays, because of so-called ionization delocalization. Improvements to the original formulation of ALCHEMI have aimed to improve the low statistical confidence level of the technique, to explicitly address ionization delocalization, and to correct for anti-site defects. The present paper will illustrate these improvements while emphasizing the basis underlying ALCHEMI analysis.
Publisher
Cambridge University Press (CUP)
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