Si. Chou et al., Spectral intensity and lineshape measurements in the first overtone band of HF using tunable diode lasers, J MOL SPECT, 195(1), 1999, pp. 123-131
High-resolution absorption Lineshapes for the P(3) and P(6) transitions of
the first overtone (upsilon = 2-0) band of HF at 296 K have been measured u
sing a pair of distributed feedback diode lasers operating near 1.31 and 1.
34 mu m, respectively. Spectral line intensities and self-broadening parame
ters were determined by fitting the measured spectra with Voigt, Galatry, a
nd Rautian lineshape models. Voigt profiles fit the low-pressure (<10 Torr)
spectra of the P(3) transition reasonably well due to the relatively stron
g collisional broadening effect. Lineshape measurements of the P(6) transit
ion (for pressures ranging from 5 to 60 Torr) show significant variation fr
om the Voigt lineshape model due to velocity-changing collisions that effec
tively reduce the Doppler component of the spectral Line. Lineshape models
that include motional (Dicke) narrowing effects, Galatry (soft collision) a
nd Rautian (hard collision) profiles yield significant improvements in the
spectral lineshape fits compared with Voigt profiles. The collisional broad
ening coefficient (gamma) of the P(6) transition obtained from a Voigt fit
is similar to 4% lower than those found with either Galatry or Rautian prof
ile fits. The measured intensities and self-broadening coefficients are com
pared with values in the HITRAN database and previous measurements. (C) 199
9 Academic Press.