Knowledge Bank

We have measured the laser spectra of hydrogen and deuterium fluoride on a high resolution vacuum spectrometer using the CO, $CO2$ and $N2O$ laser lines for calibration. All the laser transitions HF, DF and CO, $CO2$ and $N2O$ were excited in the same transversely excited cavity. The accuracy of the measurements is better than $\pm 0.003$ $cm-1$. In HF, 60 vibrational-rotational transitions were observed in the 1-0 to 6-5 bands. In addition, about 30 pure rotational transitions were observed in the ground, first and second excited levels. Similarly in DF, 50 vibrational-rotational transitions from 1-0 to 4-3 bands, have been observed. With these measurements new and improved molecular constants have been determined for HF and DF.