Historical sketch

just a few words about our background

25 March 1999

In the early eighties some people from the University of Camerino participated to the first x-ray absorption measurements collected at the national synchrotron radiation (SR) facility (ADONE @ Laboratori Nazionali di Frascati) in the framework of the PULS (Progetto per l'Utilizzazione della Luce di Sincrotrone) project. These scientists were A. Bianconi, S. Stizza and I. Davoli. Some more information about the development of Physics at Camerino can be found here.
In the late eighties Prof. S. Stizza obtained funding and attracted collaborators in forming a research group on x-ray absorption spectroscopy (XAS) at the Camerino University. Efforts were concentrated on the installation of a RIGAKU laboratory EXAFS equipment at the Centro Grandi Apparecchiature (C.I.G.A.) of the Camerino University and on the development of XAS data-analysis programs using multiple-scattering theory.
M. Berrettoni was hired as a technician for the EXAFS laboratory equipment and A. Di Cicco joined the group as a researcher.

The storage ring ADONE at Frascati (dismissed on 26-Mar-1993).
View last night at ADONE

In the early 90s the activity was concentrated on the development of advanced "ab-initio" data-analysis methods (GNXAS) in collaboration with C. R. Natoli (Laboratori Nazionali di Frascati) and A. Filipponi (Universita` dell'Aquila) and on the performance of x-ray absorption measurements at international synchrotron radiation facilities (LNF and LURE).

In the 1990-1994 period the main research activities regarded:

1) development of computer codes (GNXAS) able to use multiple-scattering (MS) theory for X-ray absorption data-analysis. This has been a long-term project research conducted mainly by Filipponi and Di Cicco and inspired by Natoli who provided also the computer codes for phase-shift generation.

2) Application of MS theory for x-ray absorption data-analysis in systems of known structure. Important initial applications were on SiX4 molecules, brominated molecules, bromine, silicon, iron.
The aim was to study distance and bond-angle distributions in molecules and crystals. This research was mainly conducted by Di Cicco and Filipponi involving also several other collaborators and research groups (S. Stizza, P. D'Angelo, V. Pavel).

3) Design and realization of XAS measurements on liquid and supercooled metals. Study of local two-atom and three-atom distributions in monoatomic liquids.
This project was realized by Filipponi and Di Cicco using dedicated SR beamtime at LURE. First experiments regarded liquid and undercooled Ga and Hg dispersed in epoxy resin.
Preliminary XAS measurements were obtained using the laboratory XAS equipment at Camerino. Other low-melting point metals (Sn, In, Pb, Bi) were investigated at LNF and LURE using conventional furnaces. Samples were realized at the University of Camerino using our Leybold metal evaporator.

4) Absorption and photoemission study of many-electron channels in core-level spectra.
The opening of two-electron channels in the atomic background of the x-ray absorption spectra was studied in silicon-based molecules, bromine and in sixth-period molten metals (Di Cicco, Filipponi and D' Angelo).
The Mg KL (1s2p) shake-up satellites in solid MgO and MgF2 were studied at Camerino University using a MAC 2 electron spectrometer and a conventional x-ray source (Di Cicco and De Crescenzi).

5) XAS studies of High-Tc superconductors and related compounds.
The local structure around Cu in YBaCuO, BSSCO and some related compounds was accurately investigated focussing the attention on the in-plane oxygen distortions (Di Cicco, Berrettoni, Stizza).

Created on 25 Mar 1999 - Responsible: A. Di Cicco
Local date/timeast:

COPYRIGHT 1996-today XAS group University of Camerino - Responsible: A. Di Cicco

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