1. Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary,
Alberta T2N 1N4, Canada
2. LPCNO, Université de Toulouse, INSA, UPS, LPCNO, 135 avenue de Rangueil,
F- 31077 Toulouse, France, and CNRS, LPCNO, F-31077 Toulouse, France
3. Institut Charles Gerhardt, Université Montpellier 2, CNRS 5253, cc 1501,
Place E. Bataillon, F-34095 Montpellier, France