References
- Leibnitz , P. unpublished results
- The authors thank E. Leibnitz for synthetic work
- Hopza , P. , Selze , H. L. and Schlag , E. W. 1993 . J. Phys. Chem. , 97 : 3937
- Craven , C. J. , Hatton , P. D. , Howard , C. J. and Pawley , G. S. 1993 . J. Chem. Phys. , 98 : 8236