Spin-effects in the ionisation-with-excitation of krypton atoms by polarised electrons

Ionisation-with-excitation has been studied for the krypton excited ionic 5 p P-4(3/2) P-4(5/2) and D-4(7/2) states which decay by emission of photons of wavelengths 465.9, 473.9 and 435.6 nm, respectively, to the lower ionic 5s P-4(5/2) state. The integrated Stokes parameters of these photons are me asured near threshold with polarised electrons and the coincidence counts b etween the scattered electrons and the decay photons as a function of the e jected electron energy and scattering angles are measured with unpolarised electrons. The integral polarisation data indicate that the residual ions c an be aligned and oriented. The electron exchange process plays a significa nt role and the spin-orbit interactions are less important than the exchang e process near threshold. The coincidence measurements show the interferenc e between ionisation-with-excitation and excitation of doubly-excited state s.