Detection of excited states by laser-induced fluorescence

Laser absorption techniques have been developed for the measurement of densities of H2 (C 3 Pi sub u) metastable densities in H2 electrical discharges. Using this technique and a modulated discharge we have found that the metastable density is proportional to discharge current density for current densities up to 10 A/sq cm. By using a pulsed laser to destroy the metastables we have obtained preliminary measurements of the metastable lifetime as a function of H2 density.