Hyperfine structure of N2 (B 3Π g andA 3Σ+ u ) from LIF measurements on a beam of metastable N2 molecules

LIF measurement of the vibrational dependence of the N2(B 3Π g ) hyperfine splitting parameters

“…The numerical analysis was greatly facilitated by auto-QI~ (8) (10,6) band of the Ne(B--A) system is shown, as scanned with the resolution of [4] (left) and with the improved resolution of the present work (right). The bottom trace gives the frequency markers from a calibrated interferometer matic measurement of the peak wavelength of each hfs component.…”

“…The resulting virtually Doppler-free LIF DC signal from a cooled PM tube is recorded as a function of laser wavelength, the scan across each rotational line covering up to ,-~0.5 GHz, depending on the width of the overall hf splitting. Important modifications of the system compared to that used in [3,4] include:…”

“…The apparatus was the same as used in the earlier work and has been described in [4]. Briefly, an intense beam of N2(A) is generated in a DC discharge struck directly in the N2 nozzle beam.…”

“…1. c) As a frequency standard, the transmission peaks of a calibrated temperature compensated and evacuated interferometer (FSR 61.77 MHz) were consistently used (while the data in [4] were based primarily on the setting of the commercial laser scan electronics, and later normalised against the interferometer).…”

“…Laserinduced fluorescence (LIF) measurements performed on such a beam in this laboratory [3,4] have yielded the corresponding hf constants for the N2(B3Hg) state. A rich pattern of term splittings as a function of the rotational quantum number could consistently be explained by fitting essentially only four magnetic hf coupling constants, while two additional quadrupole coupling constants play only a minor role.…”