The First ionization potential of element 103 successfully measured for the first time substantiated that lawrencium is the last member of actinide series

Sato, Tetsuya   

We successfully determined the first ionization potential of lawrencium (Lr, Z=103). The result experimentally substantiated for the first time that Lr is the last member of the actinide series. Measured ionization potential suggested that Lr atom would have the electronic configuration which is different from the configuration expected based on the Periodic table.