Collisional survival of antiprotonic helium atoms
2001 (English)In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 265, no 1, 47-61 p.Article in journal (Refereed) Published
We investigate the collisional survival of antiprotonic (p) over bar He+ atomcules in pure helium from a detailed ab initio analysis of their intermolecular interaction. After averaging over classical (p) over bar orbits, we attribute the collisional stability of thermalized atomcules to the existence of a high activation barrier due to Pauli repulsion. Our model predicts the reduction of the barrier for outer (p) over bar orbits, thus accounting for the quenching of high n states by He atoms. We also investigate the thermalization stage of newly formed atomcules from a classical trajectory Monte Carlo approach. Our results support the destruction of the states with n greater than or equal to 41, as well as the strong depopulation of all n < 41 layers, with a quenching rate of 50% at least. Assuming a statistical distribution of newly formed atomcules with respect to their initial angular momentum, we account for the 3% observed trapping fraction of metastable states. <(c)> 2001 Elsevier Science B.V. All rights reserved.
Place, publisher, year, edition, pages
2001. Vol. 265, no 1, 47-61 p.
IdentifiersURN: urn:nbn:se:kth:diva-20480ISI: 000167698900004OAI: oai:DiVA.org:kth-20480DiVA: diva2:339175
QC 201005252010-08-102010-08-10Bibliographically approved