1. Instituto de Física, Universidade de São Paulo, Rua do Matão 1371 CP 66318, CEP 05508-090 São Paulo, SP, Brazil
2. Department of Physics and Materials Science, University of Luxembourg, L-1511 Luxembourg City, Luxembourg
3. Department of Chemistry, Universidad Nacional de Colombia, Av. Cra. 30 #45-03, 111321 Bogotá, Colombia