[1] Pontificia Univ Catolica Rio de Janeiro, Dept Fis, BR-22452900 Rio De Janeiro, Brazil
[2] Politecn Torino, Dept Chem Engn & Mat Sci, I-10129 Turin, Italy
[3] Univ Estadual Campinas, Inst Fis Gleb Wataghin, Campinas, SP, Brazil
[4] Ecole Polytech, Montreal, PQ H3C 3A7, Canada