1. Facultad de Ciencias Naturales y Exactas, Departamento de Fisica, Universidad de Oriente; CP 90500 Santiago de Cuba Cuba
2. Computational Chemistry Research Group, Ton Duc Thang University; Ho Chi Minh City Vietnam
3. Faculty of Applied Sciences, Ton Duc Thang University; Ho Chi Minh City Vietnam
4. Department of Chemistry, KU Leuven; B-3001 Leuven Belgium