OPTOGALVANIC SPECTRUM OF AR EXCIMERS IN A DC DISCHARGE WITH SUPERSONIC EXPANSION

Optogalvanic spectra have been obtained arising from transitions betwe en electronically excited states of excimers formed in a de discharge with supersonic expansion. In this method, tunable cw laser radiation is incident on the discharge while optogalvanic signals are measured d irectly across the discharge electrodes. The primary advantage of the method is its high sensitivity, as known in atomic spectroscopy. As an example, an optogalvanic spectrum of the (IIg)-I-3 <-- (3) Sigma(u)() transition of Ar-2 near 990 nm is shown.