Investigation of the K(2S, P)-Hg interaction at collision energies between 0.5 and 6 eV

Measurements of total differential cross sections for the scattering of laser-excited K(4 2P3/2) atoms by ground state mercury atoms have been performed in a crossed beam experiment at center-of-mass energies between 0.5 and 6 eV. Characteristic features of the cross section are two well resolved rainbow structures which we can assign to the ∑ and the Π branch of the excited state potential in the scope of the elastic approximation. At energies above 2.1 eV we observe an additional structure in the cross section at large angles which shows the same dependence on the polarization as the amplitude of the ∑ rainbow. This is attributed to a shoulder in the repulsive part of the B ∑ potential. The simultaneously measured differential cross sections for the scattering of K(2S) atoms by mercury have been used to determine the repulsive portion of the ground state potential by inversion, making use of the precisely known well of the potential for this system.