Interactions of anαK−e−Atom with a He Atom

Abstract

The potential between an $\alpha K^{-}{e}^{-}$ atom and a He atom is estimated by using perturbation theory. Only those states of the $\alpha K^{-}{e}^{-}$ atom in which the $K^{-}$ meson is in a circular orbit with principal quantum number $n=27, 28, or 29$ are considered. An estimate is also made of the atomic matrix element for Stark transitions. Perturbation theory is used to calculate the $\alpha K^{-}{e}^{-}-\mathrm{He}$ interatomic potential, because it appears to give fairly reliable results for the H-He potential and because, in the particular states that are considered here, there is reason to believe that the $\alpha K^{-}{e}^{-}$ atom may be chemically somewhat similar to the ground state of the H atom. The results that are obtained indicate that the $\alpha K^{-}{e}^{-}-\mathrm{He}$ potential, like the H-He potential, is probably repulsive, except at large internuclear separations where long-range dispersion forces are dominant. The results are used elsewhere to argue that Stark transitions are likely to be suppressed, and that the rather large value of the measured mean cascade time for $K^{-}$ mesons in atomic orbits in liquid helium may, as suggested by Condo, be due to the occasional formation of a metastable state of the $\alpha K^{-}{e}^{-}$ atom.