Measurements of the ground state ionization energy and wavelengths for the 2l-nl′ transitions of Ni XIX (n=4-15) and Ge XXIII (n=7-9)

The wavelengths of the 2l-nl' (n = 4-15) spectral lines of Ne-Like Ni XIX and Ge XXIII were measured in laser-produced plasmas. The accuracy of these measurements (0.5-2.5 m Angstrom) is a large improvement over previous results, and a number of transitions (mainly from levels with n = 8-15) were observed for the first time. The 2P(3/2)-nd(5/2) and 2p(1/2)-nd(3/2) Rydberg series were used to determine the first two ionization limits of the ground states of Ni XIX and Ge XXIII. Effects of configuration interaction were observed in the intensities of some spectral lines.