MICROWAVE SPECTROSCOPY AT THE DISSOCIATION LIMIT

An ion beam technique has been developed that combines some of the met hods of mass spectrometry and molecular spectroscopy and is designed f or the study of molecular ions at energy levels lying very close to th e lowest dissociation limit. Microwave radiation is used to drive spec troscopic transitions, and electric field dissociation of the weakly b ound levels provides a high degree of state selection for sensitive de tection of the spectra. The analysis of the spectra requires unconvent ional approaches to the description of the long-range levels and their spectroscopic study and provides stringent tests of ab initio theorie s.