1. Department of Chemistry University of Hawaii at Manoa 2545 McCarthy Mall Honolulu HI 96822 USA
2. W. M. Keck Laboratory in Astrochemistry University of Hawaii at Manoa 2545 McCarthy Mall Honolulu HI 96822 USA
3. Department of Chemistry MIT Cambridge MA 02139 USA
4. Present address: Laboratory of Molecular Spectroscopy Institute of Chemistry Eötvös University Pázmány Péter sétány 1/A 1117 Budapest Hungary