Wavelengths and Energy Levels of Zn XII to Zn XX

Spectra of zinc in the ionization stages XII to XX were obtained with a laser-generated plasma and recorded photographically with a 10.7 m grazing incidence vacuum spectrograph in the range of 40 to 460 Å. Transition arrays of the type 3 s 2 3 p n -3 s 3 p n +1 and 3 s 2 3 p n -3 p n -1 3 d in the Al to Cl isoelectronic sequences were analyzed. In addition four excited configurations of Mg-like Zn were established. We present measurements of 145 spectral lines, of which 120 are newly classified. Energy levels, fitted radial integrals, and percentage compositions in LS -coupling are given. Previously classified magnetic dipole (M1) lines are compared with these levels for confirmation of their identification, and are sometimes used to improve the level values. For P-like zinc, predicted values for the M1 transitions within the ground configuration are obtained from the new levels.