1. Division of Science and Mathematics; University of Minnesota; Morris MN 56267 USA
2. Department of Physics; College of Science; University of Basrah; Basra 61004 Iraq
3. Centre for Organic Electronics; University of Newcastle; Callaghan New South Wales 2308 Australia
4. Department of Chemistry and Biochemistry; North Dakota State University; NDSU Dept. 2735, P.O. Box 6050, Fargo ND 58108-6050 USA