Abstract
High resolution differential scattering cross section measurements for KHg and CsHg were made using the method of crossed molecular beams. Up to 10 rainbow maxima for KHg and up to 14 rainbow maxima for CsHg were resolved. The intermolecular potentials were obtained from these data by direct inversion, employing the procedure described in Papers I and II. The shape of the reduced potentials for all three of the alkali‐metal‐mercury systems determined up to now by use of this inversion procedure is the same, to within the experimental errors, but it deviates significantly from that of model potentials commonly used.