1. Department
of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Gothenburg, Sweden
2. Department
of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan
3. The Swedish NMR Centre, SE-413
96 Gothenburg, Sweden
4. Department
of Mathematics and Natural Science, University of Stavanger, NO-4036 Stavanger, Norway