The muon and positron as probes of early time processes in radiation chemistry

The final spur at the end of the track of an electron or a positron in a liquid or solid contains several ion-electron pairs and possibly other reactive species. Positronium formation in condensed matter appears to occur mainly by combination of the positron with an electron in the end of track spur. Inhibition and anti-inhibition of Ps formation by particular solutes give insight to behavior in multipair spurs in radiolysis systems. In muonium chemistry there is ongoing discussion about whether muonium forms mainly by combination of the muon with an electron in an end of track spur, or whether the muon takes an electron from a molecule of the liquid while the muon still has 103-102 eV of energy and hangs onto it for the rest of the path. The discussion of the spur and hot models of muonium formation has brought forth an interesting question: what are the dynamics of electron pickup and loss by a positive particle towards the end of its track in condensed matter? How distortable is the electron cloud on the atom as it bangs through a liquid? If they begin with an atom at rest in a liquid and gradually increase its velocity of translation through the liquid, what shape does the electron cloud take? As the electron cloud is banged around like a balloon in a wind, at what velocity does it rip off?