EXCITATION OF THE COPPER RESONANCE LINES BY LOW-ENERGY ELECTRONS

The optical-excitation-function method has been used in a crossed-atom and electron-beam arrangement to measure the electron-impact cross se ction of the copper 4(2)P-->4(2)S resonance lines (324.8, 327.4 nm) fr om threshold (3.8 eV) to 8 eV. Relative experimental cross-section dat a are normalized at an energy of 1000 eV with respect to first Born th eory that includes the 4(2)S-->4(2)P resonance transition with an osci llator strength of 0.652 and cascading from the (3d10nd)2D states with n=4, . . . , 10. The measured Cu 4(2)S-->4(2)P cross section is compa red with recent theoretical calculations in close-coupling approximati on. Very good agreement is found with the ten-state close-coupling the ory of Scheibner and Hazi (private communication).