Threshold-ion-pair-production spectroscopy of H₂S and D₂S

The threshold-ion-pair-production (TIPP) spectra of H2S and D2S have been recorded in the vicinity H++SH?[X1?+(v?=0,1;J?)] D++SD?[X1?+(v?=0,1;J?)] thresholds using a tunable vacuum-ultraviolet laser cold molecular samples (Trot?20K) supersonic expansions. ion-pair-production signal was found to be much stronger at v?=0 than v?=1 thresholds. From rotational structure spectra, dominant photodissociation partial waves are determined those with l?2, which indicates that dissociative Rydberg states linear ion core involved formation ion-pair states. H + +SH ? ion-pair-dissociation threshold energy we derive for is excellent agreement value reported an earlier TIPP-spectroscopic investigation by Shiell et al. [J. Phys. Chem. A 104 (19), 4339–4342 (2000)]. our new values thresholds, determine improved bond-dissociation energies D0(H?SH) D0(D?SD) 31449(2)cm?1 31999(17)cm?1, respectively, where numbers parentheses represent uncertainty 1? units last digit.