Knowledge Bank

A pulsed tunable dye laser has been used to excite over 350 optogalvanic (OG) transitions in the wavelength region 337-598 nm using a commercial Fe-Ne hollow cathode discharge lamp. Around 220 of these OG transitions have been identified to be associated with energy levels belonging to neon. Interference fringes obtained simultaneously employing a low-finesse etalon have permitted calibration of the dye laser frequency to within an estimated accuracy of $0.3cm-1$. Several of the observed OG transitions originate from metastable states of neon. A digital oscilloscope was used to record the waveforms of the OG transitions. Polarities of 29 identifiable neon transitions observed in the near UV and visible are understood in terms of processes that affect the population of atoms I metastable state. The OG signals together with the etalon fringes have made possible accurate calibration of rotationally-resolved laser excitation spectra of free radicals in a supersonic jet environment.