Shapes of optical emission lines from atoms excited by fast ion impact. II. Initial experimental results

Abstract

We present initial results of a new technique in which differential cross-section information is obtained by measuring the spectral line shape of emitted lines. We have measured the spectral line shape of the lithium resonance line at 670.7 nm (1s22s2S–1s22p2P) emitted following 5 keV Li+–He collision and compared it to the shape predicted on the basis of measured and theoretical cross sections using the method developed in paper I. Although broadening effects due to the particular experimental conditions used mask the details near the line centre, the shape of the wings of the line suggest that there is a significant amount of large angle scattering. The limitations of this new technique are discussed and it is concluded that, in the present case, cascade contribution to the population of the upper state is the most likely difficulty.