Electric field quenching of long-lived states in H3

Due to its simple structure, neutral H3 qualifies as a model-system for observations of dynamics inside molecules. Our focus lies on the three-body-decay into three single H-atoms H(1s)+H(1s)+H(1s) which provides direct insight into the effects of non-adiabatic coupling. Using triple-coincidence techniques, the momentum-correlations of the fragment atoms are determined and visualized in so-called Dalitz-plots. In the experiment we control the predissociation of H3 in the metastable 2p state by applying an electric field. In this fashion an adjustable amplitude of the short-lived 2s state can be mixed into the 2p state. The experiment shows, that with increasing field strength the decay behaviour of the 2p acquires that of the 2s state. In addition we present measurements, which demonstrate the existence of highly excited, long-lived states close to the ionization limit. In order to characterize them, we once again use an electric field. At well defined spatial location, the admixture of short-lived states leads to a quenching of their lifetimes. In this way we achieve an improved energy-resolution and higher dissociation-rate which may help identify these currently unknown states.