1. Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, USA
2. São Carlos Institute of Physics, University of São Paulo, PO Box 369, 13560-970 São Carlos, SP, Brazil
3. Beijing Computational Science Research Center, Beijing 100094, China
4. São Carlos Institute of Chemistry, University of São Paulo, PO Box 780, 13560-970 São Carlos, SP, Brazil