			15min:

THRESHOLD ION-PAIR PRODUCTION SPECTROSCOPY (TIPPS) of H₂ and D₂.

X. K. HU, R. C. SHIELL, Q. J. HU AND J. W. HEPBURN, Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.

Threshold Ion-Pair Production Spectroscopy (TIPPS) can determine field-free energetic thresholds for ion-pair formation in the same way that pulsed field ionization techniques (ZEKE/MATI) can obtain field-free ionization potentials. H₂ and D₂were investigated and their ion-pair thresholds were determined to be 139714.8 \pm 1.0 cm^-1 and 140370 \pm 1.0 cm^-1, respectively. Pulsed field ion-pair formation mostly results from excitation of complex resonances between ion-pairs and electronic Rydberg states of the parent molecule. However, evidence of the direct excitation of ion-pair Rydberg states was also found.