The photoionization cross section of Mgr near threshold in the region between 160 -100 nm was studied using synchrotron radiation, an atomic-beam technique, and a time-of-flight mass spectrorneter for the selective detection of the Mg+ photoions. Special attention was given to the signals of the double electron resonances 3pns and 3pnd 'Pl in comparison with theoretical calculations and recent experiments.

Monochromatized synchrotron radiation, atomic beam technique and a TOF spectrometer were used to measure the cross section of single and double photoionization of the lanthanide elements in the region of the 5p excitation. A systematic difference between light and heavy elements was observed