1. Instituto de Estructura de la Materia; IEM-CSIC; Serrano 121 28006 Madrid Spain
2. Department of Chemistry and Center of Analysis of Structures and Interfaces (CASI); The City College of New York; New York 10031 USA
3. Southern Connecticut State University; 501 Crescent Street New Haven 06515 CT USA
4. Department of Scientific Research, The Metropolitan Museum of Art; 1000 Fifth Avenue New York 10028 NY USA