Second spectrum of Manganese (Mn II), Part I: Fine and hyperfine structure analysis of even-parity levels

We have taken advantage of the existence of some experimental Mn II hyperfine magnetic dipole constant (A) values given in literature with low uncertainties to achieve for a first time an accurate hyperfine structure (hfs) parametric study. The monoelectronic hfs parameter values were extracted in their entirety for the alone stable 55Mn II. For example for 3d44s configuration we obtain: a4s10=198.08 mk and a3d01=17.14 mk. These semi-empirically extracted single-electron parameters were analyzed and compared with ab-initio calculations. In this first part of a global work, devoted particularly to even-parity levels we have at beginning studied a fine structure of two hundred levels, giving their leading eigenvector percentages and their calculated Landé-factor gJ. We present also predicted singlet, triplet and quintet positions of missing experimental levels up to 120 000 cm−1, not far from Mn II ionization energy of 126 000 cm−1. We close this work by giving predicted values of magnetic dipole hfs constants of all known levels of the most relevant Mn II even-parity configuration: 3d44s, whose splitting is not yet measured.