Atomic, Molecular, and Optical Physics Seminar
Measuring the Dissociation Energies of Molecular Hydrogen and Its Ion
University of Connecticut
After many years of effort, we have completed a multi-faceted program to study the second dissociation limit of molecular hydrogen with very high resolution, including selective detection of dissociated hydrogen atoms in the 2s or 2p states. Both the highest bound vibrational levels and the adjoining continuum have been studied with a resolution of about 0.01--0.02 cm-1, which we believe is the best resolution so far attained for any molecular photodissociation continuum. Three principal types of information are obtained from these experiments: the binding energy of molecular hydrogen, the level structure of the highest bound levels, and the details of the structure of the near-threshold continuum, including atomic branching ratios. We have obtained improved measurements of the dissociation energies of all three stable isotopic variants of H2, as well as their molecular ions, with accuracies as good as 0.004 cm-1. The accuracy is better than a factor of 5--10 better than previous work, and sets a new benchmark for fundamental molecular physics calculations. Agreement with the most recent theoretical calculations is good for H2 and D2, although not for HD.
Monday, March 21, 2005
Gant Science Complex