CONTRIBUTION OF TRANSFER IONIZATION TO CUSP ELECTRON PRODUCTION IN PROTON ON ARGON COLLISIONS

Cusp-electron emission in proton on argon collisions has been investig ated at impact energies 33, 50 and 75 keV. By detecting the electrons in coincidence with the charge-state analysed outgoing H-+.0 projectil es, the process of electron capture to the continuum (Ecc), as well as the process of simultaneous ECC and bound-state capture (transfer ion ization, TI) were identified. The ratios of the yields for cusp-electr on production by TI and ECC are found to decrease with increasing proj ectile energies. At the lowest proton energy (33 keV) the measured TI/ ECC ratio is about four times smaller than the corresponding ratio for incident He+ measured in earlier work. Significant is the finding tha t there exists a cusp associated with TI events, and, moreover, that t his cusp is present for neutral outgoing projectiles.