Laser spectroscopy of molecular ions in an ion beam

The operation of a coaxial ion beam/laser beam experimental apparatus is described, in which an ion beam is overlapped by a laser beam and the ions are Doppler-tuned into resonance. The experimental apparatus is suitable for the study of both positive and negative ions. Resonant transitions are reported in C{dollar}\sb2\sp{-}{dollar} and in CO{dollar}\sp{+}{dollar}. In C{dollar}\sb2\sp{-}{dollar}, a two-photon resonant photodetachment experiment was performed, with detection of fast neutral C{dollar}\sb2{dollar}. The experiment yields a measurement of the R(10) line of the 1-0 band in the B-X electronic transition. In CO{dollar}\sp{+}{dollar}, the blended Q(1) and R(12) lines of the A-X electronic transition were observed using collisional detection. In both ions, the results reported here are in good agreement with previous results by other workers