1. Department of Chemistry and W. M. Keck Research Laboratory in Astrochemistry University of Hawaii at Manoa Honolulu Hawaii 96822 USA
2. Permanent Address: Laboratory of Molecular Spectroscopy, Institute of Chemistry Eötvös University PO Box 32 H-1518 Budapest 112 Hungary
3. Present address: Berlin Institute of Technology, IOAP Hardenbergstrasse 36 10623 Berlin Germany