1. O. P. Charkin, N. M. Klimenko, and D. O. Charkin, Zh. Neorg. Khim. 53(4), 5239 (2008) [Russ. J. Inorg. Chem. 53 (4), 568 (2008)].
2. J. Sun, W.-C. Lu, W. Zhang, et al., Inorg. Chem. 47, 2274 (2008).
3. M. Frish et al., GAUSSIAN 03, Revision B.03, Gaussian, Inc., Pittsburgh, PA, 2003.
4. A. D. Becke, J. Chem. Phys. 98, 5648 (1993).
5. C. Lee, W. Yang, and R. G. Parr, Phys. Rev. B: Condens. Matter 37, 785 (1988).