1. Department of Chemistry, Ecole
Normale Supérieure, 24 rue Lhomond, 75005 Paris, France
2. Université Pierre et
Marie Curie Paris 6, 4 place Jussieu, 75005 Paris, France
3. UMR 8640, Centre National de la
Recherche Scientifique, Paris, France
4. Department of Physics, Faculty
of Sciences, Kyushu University, Fukuoka 812-8581, Japan