Photoion spectroscopy of atomic Ho, Er and Tm in the region of the 4d giant resonances

Abstract

Using synchrotron radiation in combination with atomic beam and time-of-flight technique, the partial ion yield spectra sigma (Xn+) of Ho, Er and Tm in the region between 130-200 eV were measured. The signals are dominated by Fano-type resonances of singly charged photoions sigma (X+) which can be attributed to discrete transitions X4d104fn to X4d94fn+1 followed by the autoionization process X4d94fn+1 to X+4d104fn-1+ epsilon d,g. This interpretation is corroborated by ab initio Hartree-Fock calculations of the resonant photoabsorption cross section.