Abstract
Antiproton and negative muon captures by helium and neon atoms are treated using the fermion- molecular-dynamics method, yielding capture cross sections, initial quantum numbers, and ejected-electron energies. The calculated angular-momentum distributions tend to pile up at and are not well fitted by the form which is often assumed in experimental analyses. The residual electrons are generally left in a “shake-up” state. When capture is accompanied by multiple ionization, the second and later electrons escape with increasing kinetic energies, a process that is not well described as quasiadiabatic. In a 50:50 mixture of helium and neon, the calculated Ne:He capture ratios are 3.36 for and 3.69 for The per-atom capture probability is almost independent of the neon fraction and is in overall agreement with several and experiments; for there is a rather strong dependence on neon fraction, but there are as yet no experiments. The possible experimental indication of a strong isotope effect on capture of in mixtures of and is not supported by the present calculation.
- Received 9 December 1999
DOI:https://doi.org/10.1103/PhysRevA.62.022512
©2000 American Physical Society