1. D. K. Roy, A. Saha, and A. K. Mukherjee, Spectochim. Acta A 61, 2017 (2005).
2. R. S. Mulliken, J. Am. Chem. Soc. 72, 600 (1950).
3. R. S. Mulliken and W. B. Pearson, Molecular Complexes (Wiley, New York, 1969).
4. R. Foster, Charge Transfer Complexes (Academic, London, 1969).
5. M. M. A. Hamed, M. I. Abdel-Hamid, and M. R. Mahmoud, Monatsh. Chem. 129, 121 (1998).