Large-angle scattering and nuclear resonance effect in electron capture by protons

In an ion-atom collision accompanied by nuclear scattering, several scattering-and-capture amplitudes can contribute to the total amplitude for capture. If the bombarding energy corresponds to a nuclear resonance energy, interference between these amplitudes can occur which reflects the rapid energy dependence of the nuclear scattering amplitude. Electron capture probabilities, which are derived from the square of the total amplitude for capture, reproduce this interference effect. We have investigated electron capture accompanied by nuclear scattering by studying the probabilities for electron capture from neon-20, nitrogen-14, and carbon-12 at 150 degrees and 30 degrees with proton bombarding energies between 0.5 and 1.5 million electron volts. We then examined the probability for electron capture by protons in the vicinity of the 0.462 million electron volt elastic nuclear resonance in carbon-12, the 1.058 million electron volt elastic resonance in nitrogen-14, and the 1.510 million electron volt elastic nuclear resonance in neon-22. We have found a large nuclear resonance effect on electron capture in the latter case. All the data is in qualitative agreement with theoretical calculations by Jakubassa-Amundsen and Amundsen, based on the strong potential Born approximation for electron capture