Excitation Potentials and Shell Corrections for the Elements Z2=20 to Z2=30

Excitation potentials and shell corrections for the elements Z 2=20 to Z2=30 are evaluated from experimental stopping-power data for 5-12-MeV protons and deuterons. Use is made of Walske's K- and L-shell corrections and shell corrections calculated by Bonderup (1967) on the basis of the Thomas-Fermi model. It is suggested that Cu be used rather than Al as a standard for stopping-power measurements. ICu is deduced to be 320.8±3.8 eV. Relative stopping-power measurements by Bakker and Segre, by Teasdale, by Burkig et al., and by Nakano et al. are normalized to Cu, and mean excitation potentials are found by means of Bonderup's shell corrections. Within the Z2 interval treated here, it is found that I/Z2 increases with increasing Z2, contrary to the general trend through the periodic system of elements