Transition from monolayer-thick 2D to 3D nano-clusters on α-AlO(0001).

This paper reports on the long-standing puzzle of the atomic structure of the Ag/α-AlO(0001) interface by combining X-ray absorption spectroscopy, to determine Ag local environment [ average Ag-Ag () and Ag-O () interatomic distances and Ag coordination numbers (CN)], and numerical simulations on nanometric-sized particles. The experimental key was the capability of a structural study of clusters involving only a few atoms. The concomitant decrease of and CN with decreasing cluster size provides unambiguous fingerprints for the dimensionality of the Ag clusters in the subnanometric regime leading to a series of unexpected results regarding the size-dependent interface structures.

Local environment of iodine dissolved as iodate in high-pressure aluminoborosilicate glasses: A I K-edge x-ray absorption spectroscopic study.

The use of high-pressure synthesis conditions to produce I-bearing aluminoborosilicate represents a promising issue for the immobilization of I radioisotope. Furthermore, iodine appears to be more solubilized in glasses under its iodate (I) form rather than its iodide (I) form. Currently, the local atomic environment for iodine is poorly constrained for I and virtually unknown for I or I.

Electron beam analysis induces Cl vacancy defects in a NaCl thin film.

This work reports on the electron-induced modification of NaCl thin film grown on Ag(110). We show using low energy electron diffraction that electron beam bombardment leads to desorption and formation of Cl vacancy defects on NaCl surface. The topographic structure of these defects is studied using scanning tunneling microscopy (STM) showing the Cl defects as depressions on the NaCl surface.

Core level shifts as indicators of Cr chemistry on hydroxylated α-AlO(0001): a combined photoemission and first-principles study.

The Cr/α-AlO(0001) interface has been explored by X-ray photoemission spectroscopy, X-ray absorption spectroscopy (XAS) and first-principles calculations of core level shifts including final state effects. After an initial oxidation a reaction with residual surface OH but no reduction of the alumina substrate, Cr grows in a metallic form without any chemical effect on the initially oxidized Cr. However, Cr metal lacks crystallinity.