STRONG EFFECTS OF INITIAL ORBITAL ALIGNMENT OBSERVED FOR ELECTRON-CAPTURE IN KEV H+-NA(3P) COLLISIONS

Electron capture in keV collisions of protons with sodium atoms in the excited Na(3p) state is studied. The initial orbital alignment of the valence electron is controlled by the polarization of the exciting light. Capture into H(n) levels is measured for light polarization parallel and perpendicular to the proton beam direction. For n=2 the capture cross section is about 35% larger for an orbital aligned parallel than for one perpendicular to the beam direction, at all energies. However, for n3 the alignment effect varies dramatically with energy, supporting recent theoretical results. © 1990 The American Physical Society.