1. LCPO-CNRS-ENSCPB and Bordeaux University I, 16 Avenue Pey Berland, 33607 Pessac Cedex, France, Departamento de Quimica, Universidade Federal de Santa Catarina, Florianopolis, Brazil, CERMAV-CNRS affiliated with Joseph Fourier University, Grenoble, France, CRESMAP, Université de Mons-Hainaut, Mons, Belgium, and ESRF, Grenoble, France