Acknoledgements

I would like to thank the following people

Dr Henry S. Rzepa* for his excellent guidance.
Omer Casher*, Chris Leech*, and Wyn Locke* and for their help and their support.
Chris Page* for his help, his support and for checking this report.
Pr J.-Y. Lallemand** and Dr S. Zard** for the connection between Imperial College and the Ecole Polytechnique.

* Imperial College of Science Technology and Medicine, Department of Chemistry, LONDON (U.K.).

**Ecole Polytechnique, PALAISEAU (FRANCE)