Millimetre wave spectrum of the weakly bound complex NH3-N-2

The van der Waals complex NH3-N-2 has been studied in the millimetre wave r egion, 76-106 GHz. Thirty-five lines were observed and assigned as pure rot ational transitions, R(11) to R(15), belonging to six series involving all combinations of the parent molecule nuclear spin species, ortho/para-ammoni a and ortho/para-nitrogen. Two of these series are continuations to higher J values of transitions observed previously in the microwave region, and th e other four series were observed here for the first time. Predictions are given for a number of new NH3-N-2 microwave transitions, and future observa tions of these should help to confirm the assignments given here. The time is ripe for theoretical investigations of NH3-N-2 and the isoelectronic com plex NH3-CO.