Optoacoustic measurement of HCI specific absorption coefficients at DF laser wavelengths

A resonant optoacoustic cell was used to determine the specific absorption coefficients of small HCI admixtures to atmospheric nitrogen at the DF laser lines P(2)(3), P(2)(4), and P(2)(5). The cell was calibrated using absolute absorption coefficients of N(2)O measured with a multipass absorption cell. Effects of corrosive action and the relatively long relaxation time of the HCI-N(2) mixture were carefully eliminated. The measured specific absorption coefficients of 510,15, and 1.4 m(-1) atm(-1) at laser lines P(2)(3), P(2)(4), and P(2)(5) agree well with values calculated from absorption line parameters and are in fair agreement with older experimental results.