The forward-scattered light observed when a single-mode dye laser interacts with the three neon transitions 1s5(J = 2)-2p8(J = 2), 1s3(J = 0)-2p5(J = 1), and 1s4(J = 1)-2p7(J = 1) has been investigated as an applied longitudinal magnetic field is varied. The 1s5 and the 1s3 states are metastable. This condition allows a comparison of the spectra for the cases 1s5(J = 2)-2p8(J = 2) and 1s3(J = 0)-2p5(J = 1) in order to discuss whether the complex line shapes obtained for the J = 2 to J = 2 atomic system are due to higher-order coherences or whether they originate from coherences between m = ±1 states. Experimental and calculated line shapes are presented. The calculations have been performed with the use of a semiclassical model for the light/matter interaction. A J = 0 to J = 1 (or a J = 1 to J = 1) model reproduces the overall shapes of the recorded spectra for all three transitions. The results show that, even when laser beam spatial effects and the sample isotopic effects are taken into account, interpretations of forward-scattering spectra in order to determine atomic parameters can reliably be done for simple J = 0 to J - 1 systems only.
Åsa Lindberg, "Magneto-optic Spectroscopy on Neon Using Laser-Induced Forward Scattering," Appl. Spectrosc. 48, 1532-1538 (1994)