1. Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
2. MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand
3. Department of Mathematics and Statistics, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
4. Department of Physics, University of Auckland, Auckland 1010, New Zealand