Hyperfine structure measurements of neutral iodine atom (127I) using Fourier Transform Spectrometry

•Hfs splittings measured in the 183 lines of II in near infrared.•New hfs A and B constants presented for 5 even levels.•New hfs A and B constants reported for 4 odd levels.•Improved hfs A and B constants derived for 25 even and 26 odd levels.

We report the hyperfine Structure (hfs) splitting observations of neutral iodine atom (II) in the 6000 - 10,000 cm−1 near infrared spectral region. The measurements were carried out using a high-resolution Fourier Transform Spectrometer (FTS), where an electrodeless discharge lamp (EDL), excited using microwaves, was employed as the light source and InGaAs as the light detector. A specially designed setup was used to lower the plasma temperature of the medium so as to reduce the Doppler width and consequently to increase the spectral resolution of hfs components. A total of 183 lines with hfs splitting have been observed, out of which hfs in 53 spectral lines are reported for the first time. On the basis of hfs analysis, we derived the magnetic dipole and electric quadrupole coupling constants, A and B respectively for 30 even and 30 odd energy levels and are compared with the values available in the literature. New hfs values for 5 even and 4 odd levels are also reported here for the first time.

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