Lyman-α1 decay in hydrogenlike ions:: Interference between the E1 and M2 transition amplitudes -: art. no. 153001

For the Lyman-alpha(1) transition (2p(3/2) --> 1s(1/2)) in hydrogenlike ions an interference between the leading E1 decay channel and the much weaker M2 multipole transition gives rise to a remarkable modified angular distribution of the emitted photons from aligned ions. This effect is most pronounced for the heaviest elements but results in a still sizable correction for medium-Z ions. For the particular case of hydrogenlike uranium where the angular distribution of the Lyman-alpha(1) x rays following radiative electron capture has been measured, the former variance with theoretical findings is removed when this E1-M2 interference is taken into account.