Laser optogalvanic effect in a pure iodine discharge

Abstract

Doppler-limited optogalvanic spectra are obtained by irradiating an iodine discharge with a cw dye laser. The discrete lines of the Iz B-X system appear superimposed on a weak continuum; atomic I lines (neutral and ionic) are also found. The B-X spectrum closely tracks the fluorescence excitation spectrum except when the laser beam coincides with the discharge axis. When excitation transverse to the discharge is used, an optogalvanic effect can be detected far outside the discharge region. In addition, the signal changes sign along the discharge axis, suggesting that more than one mechanism contributes to the optogalvanic effect in iodine.