2011 Articles

Associative detachment of H- + H → H2 + e-

Miller, K. A.; Bruhns, H.; Eliášek, J.; Čížek, M.; Kreckel, H.; Urbain, X.; Savin, Daniel Wolf

Using a merged-beams apparatus, we have measured the associative detachment (AD) reaction of H − + H → H 2 + e − for relative collision energies up to E r ≤ 4.83 eV. These data extend above the 1-eV limit of our earlier results. We have also updated our previous theoretical work to account for AD via the repulsive 2 Σ + g H 2 − potential energy surface and for the effects at E r ≥ 0.76 eV on the experimental results due to the formation of long-lived H 2 resonances lying above the H + H separated atoms limit. Merging both experimental data sets, our results are in good agreement with our new theoretical calculations and confirm the prediction that this reaction essentially turns off for E r ≳ 2 eV. Similar behavior has been predicted for the formation of protonium from collisions of antiprotons and hydrogen atoms.