Determination of absolute light-scattering cross sections of molten salts

Systematic measurements have been made of absolute light‐scattering cross sections of molten alkali halides by comparing in situ the scattering intensities of the melts to that of the 992‐cm−1 line of benzene which has been used as intensity standard. All measurements have been made at about 30° above the melting point and from a low‐frequency shift (ν) limit of 4 cm−1 to the highest possible, depending on the salt. The experimental method and comparison procedures (including data corrections) are described along with calculations of the solid angle of collection of the optical system. The resulting differential cross sections for polarized scattering vary between 2.3 × 10−29 (LiCl) and 1.2 × 10−28 cm2/ion pair sr (CsI), showing, in general, the anticipated trends with ion size and polarizability, that is, the larger the ion (the higher the polarizability), the more efficient the scatterer.