THE INVESTIGATION OF THE SATELLITE RAINBOW IN THE SPECTRA OF DIATOMIC-MOLECULES

A refinement of the theoretical model for the description of the shape of a satellite rainbow in the spectra of diatomic molecules, based on the uniform Airy approximation, is presented. The satellite rainbow in the red wing of the caesium 852.1 nm line has been measured by means of classical absorption spectroscopy and excellent agreement with the calculated shape is found. The method for the quasistatical singularity position determination from the position of the minimum of the first derivative of the reduced absorption coefficient is proposed. The first derivative of the experimentally determined reduced absorption coefficient with respect to wavelength gives the position of the quasistatical singularity of the satellite rainbow to be 857.32 +/- 0.02 nm, while our theoretical calculations predict its position at 857.36 nm.