Observation of dipole–dipole pair absorption using optogalvanic detection

Abstract

The first reported use is described of optogalvanic detection to observe laser-induced, dipole–dipole pair absorption in discharges of barium and helium–barium. Fractional changes in steady-state discharge populations as small as one part in 10⁵ that are due to the laser-induced collision are observed. In both experiments the absorption maxima occur at the predicted (R = ∞) wavelength and have a full width at half-maximum of approximately 15 cm⁻¹.