L3-SUBSHELL ALIGNMENT OF MAGNESIUM AFTER ELECTRON-CAPTURE BY PROTONS

We have measured the alignment of Mg+ (L3) ions after electron capture by H+ in the energy range E(H+) = 40-240 keV (range of relative veloc ity v(H+)/v(L3) = 0.6-1.5) via the coincidences between the non-isotro pically emitted L3-M1M1 Auger electrons and the neutral H atoms. Our e xperimental results show a strong resonance-like behaviour of the alig nment values A20c as function of relative velocity with a maximum at a bout v(H+)/v(L3) = 0.8. This is in qualitative agreement with the theo retical values obtained with the Oppenheimer-Brinkmann-Kramers (OBK) a pproximation. The tendency of the experimental alignment results towar ds large negative values at high collision velocities is in accordance with the high-velocity behaviour of the OBK approximation and the sem iclassical impulse approximation.