CO2-laser photoacoustic detection of heavy water vapour

A CO2 laser cw system and a photoacoustic detection apparatus, based on a nonresonant gas cell, was constructed. Coincidences of D2O absorption with several laser lines were observed. The strongest absorption was observed with the line at 9.26 μm. Samples of deuterated water were used to examine the behaviour of the photoacoustic signal under conditions of varying deuterium content and total vapour pressure. A principal calibration procedure is proposed. The behaviour of the system on buffer gas introduction was examined with hydrogen and dry air. Self-buffering of water vapour is also discussed. (author) 23 refs.; 5 figs