Photoacoustic distributed feedback laser spectroscopy on hydrogen fluoride

We have developed a photoacoustic spectrometer based on a distributed feedback (DFB) diode laser. The single-mode emission of the laser can be tuned continuously over 700 GHz enabling the precise determination of absorption line parameters. Our experiments were performed on the rotational lines P2 and P3 of the vibrational transition 2-0 (overtone) of hydrogen fluoride (HF) at 1304.534 nm and 1312.591 nm (vacuum), respectively. The pressure broadening coefficient due to elastic collisions with N(2) molecules is found to be 5.92 +/- 0.04 GHz/atm (296 K) and 5.38 +/- 0.04 GHz/atm, respectively. The Doppler linewidths turn out to be 630 +/- 40 MHz and 670 +/- 40 MHz (296 K), respectively. The pressure-induced line shifts of the absorption lines for N(2) are 540 +/- 40 MHz/ atm and 580 +/- 40 MHz/atm, respectively.