Initial population of? ?,? ?,K ? after radiative atomic recombination

Abstract

We calculate the radiative atomic recombination of # , ~r , K-with a nucleus. In the initial state the negative particle moves in a Coulomb field, in the continuous spectrum, with positive energy and is captured into the bound orbit (n, l) of negative energy. We consider the exotic atom as a hydrogenic atom. The analytical expression of the recombination cross section, together with a "low energy" approximation, is derived. We obtain information on the atomic initial population: the results presented here show that the Bohr statistical distribution, used in the case of neutral atoms, is not correct in this case.

Laser-enhanced electron-ion capture and antihydrogen formation

“…iv) As shown recently (see, for instance, [9]), the population of l sublevels reaches, for low energies and n> 3, a maximum at intermediate I values and then falls off rapidly. For a given electron velocity G the total spontaneous capture rate r ~p~ per ion (at rest) is…”

Coulomb formation and evolution of muonium in vacuum

“…" ~J The present results are deduced from the Coulomb capture cross sections previously derived in a completely analytical approach [14,15]. An initial population of the 2p level comparable to the 2 s population is obtained.…”

“…Knowledge of the time evolution of the initial population allows one to know the exact population at the time when the measurement of the light emitted by muonium is executed. The explicit expression of the Coulomb formation cross section is the following [15]:…”

Radiative recombination rates with different statistical distributions

“…Recently we have obtained a very precise parametrization of the cross section based on the exact computation of the non-confluent hypergeometrical functions and also derived high energy and low energy approximations to the cross section [15]. Reference [15] is the starting point of the present work (see also our previous works of [16,17] for further details), in which we are interested in computing and giving a parametrization of the radiative recombination rates averaged over Maxwellian and non-Maxwellian distributions of velocities. In fact, radiative recombination can occur in the presence of an electromagnetic field, for instance laser radiation or simply a static electric field (Druyvenstein effect [18,19]), or generally in the presence of an average external field in such a way that non-Maxwellian distributions must be used [20,21].…”