Theoretical assignment of the observed hyperfine structure in the saturated absorption spectra of I 2129 and I 127I 129 vapors in the 633 nm wavelength region

Abstract

The detailed structure observed in the saturated absorption spectrum of I 2 129 vapor in the 633 nm wavelength region in the spectral interval reported by Knox and Pao, has been interpreted to be the overlap between the hyperfine lines of the 8-4 P(54) line of I 2 129 and the 6-3 P(33) line of the I 127I 129 vapor. In this assignment, the nuclear electric quadrupole and nuclear magnetic terms in the Hamiltonian were diagonalized exactly and certain molecular parameters were varied to obtain the best fit with the observed spectrum. For I 2 129, the calculated distance (separation) of the center of the 8-4 P(54) line from the line center of the Ne 20 633 nm laser transition is 0.04 cm −1 and the RMS deviation between the theoretical and experimental hyperfine spectra is 0.3 MHz. Although the calculated frequency of R(60) transition in the 8-4 band is only 0.03 cm −1 from the center of the laser line, we conclude on the basis of the larger RMS error (0.5 MHz) that this latter transition is less likely to be that responsible for the structure discussed in this paper.