Quenching of individual metastable states of antiprotonic helium (p̄He+) in collisions with H2 and D2 in gas phase was studied using a laser-resonance method at CERN's Antiproton Decelerator. The temperature dependence of the quenching cross-sections of the p̄He+ states (n,l) = (37,34), (38,35), and (38,37) in the reactions [p̄He+](n,l)+H2 and [p̄He+](n,l)+D2 was investigated in the temperature range of 25-300 K. Significant quantum tunnelling effects were revealed at low temperatures and (n,l)-dependent reaction barriers were deduced, in good agreement with recent theoretical calculations.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry