1. Contribution from the Chemistry Department, University of Glasgow, G12 8QQ, United Kingdom, ISIS Fascility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, United Kingdom, Technical University of Szczecin, ul. Piastów 42, 71-065 Szczecin, Poland, and Department of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warszawa, Poland