HIGH-RESOLUTION PHOTOION YIELD MEASUREMENTS OF HOLLOW ATOMIC LITHIUM

Using monochromatized extreme-vv radiation from the undulator beamline BW3 at HASYLAB we have measured at high resolution (E/Delta E similar to 7000) the Li+ photoion yield spectrum at excitation energies corre sponding to transitions to double K-shell vacancy states. A number of such resonances including single-photon-three-electron excitations, e. g. 1s(2)2s(S-2) --> 2p(3)((2)p), have been observed for the first time . The spectrum is tentatively classified with the aid of Hartree-Fock calculations.