Prospects for precision measurements on ammonia molecules in a fountain H. L. Bethlem, M. Kajita, B. Sartakov, G. Meijer and W. Ubachs Eur. Phys. J. Special Topics, 163 (2008) 55-69 Published online: 25 October 2008 DOI: 10.1140/epjst/e2008-00809-5