Electron Capture to Continuum States From Inner Shells

The capture of an electron from an inner atomic shell, namely, from the argon L shell, into projectile continuum states [electron capture to the continuum, (ECC)] has been observed for proton impact around 300-keV collision energy. The energy distribution of ejected electrons detected in forward direction in coincidence with LMM Auger electrons shows the pronounced cusp-shaped peak characteristic for the ECC process. This also provides the first ECC measurement in the low-impact-velocity regime.