Search for projectile charge dependence of kinetic electron emission from clean polycrystalline gold

Total yields for ion-induced electron emission from atomically clean polycr ystalline gold have been measured accurately (total errors less than or equ al to +/-5%) for normal incidence of Cq+ (q less than or equal to 5)-, Nq+( q less than or equal to 6)-, Oq+(q less than or equal to 7)- and Neq+(q les s than or equal to 9) ions with impact velocities from below 10(5) m/s (exc lusive potential emission/PE regime) up to 10(6) m/s (5 keV/amu). Contribut ion from kinetic emission (KE) to these total yields was studied by taking into account the respective PE yields and precise determination of the KE i mpact velocity threshold for corresponding singly charged ions. For given i on species Z(1) and impact velocity we have investigated whether KE yields depend on the ion charge state q. From q = 1 toward 3 a slight decrease wit h q has been found, but there are no significant differences in KE yields a t higher q values. Results are discussed in view of the q-dependence for re levant KE mechanisms. (C) 1999 Elsevier Science B.V. All rights reserved.