Infrared Spectra of Hot HF and DF

New Fourier transform emission measurements were obtained for HF and DF at a temperature of 2300°C. Both pure rotation and vibration-rotation lines were measured with a precision of about 0.0005 cm-1. These new lines were combined with previously measured data to give improved rotational constants for the vibrational levels υ = 0-5. The HF molecule is the most convenient monitor of 19F abundances in cool stars.