1. Department of Physics, FCT; UNESP Univ Estadual Paulista, Rua Roberto Simonsen 305, Presidente Prudente; Sao Paulo 19060-900 Brazil
2. Division of Research and Extension, Faculty of Presidente Prudente-FAPEPE; União Nacional das Inst. de Ensino Superior Privadas-UNIESP, Avenue Presidente Prudente 6093; Presidente Prudente São Paulo 19053-210 Brazil
3. Faculty of Chemical Science and Engineering, Center for Research in Engineering and Applied Sciences; UAEM, Avenue Universidad 1001; Cuernavaca Morelos 62209 Mexico