LINEWIDTHS OF SINGLY CHARGED, NOBLE-GAS IONS FROM BORN AND BORN-ROBB APPROXIMATIONS - DEPENDENCE WITH ATOMIC PARAMETERS AND ELECTRON-DENSITY

The linewidths of the ns-np transitions (n = n0 + 1, n0 being the principal quantum number of the ground level) for the homologous sequence Ne II, Ar II, Kr II and Xe II, were calculated using analytical expressions for the cross-sections and rate coefficients. The data are in fair agreement with the experimental results, and a least squares fit to all theoretical values obtained, gives a relation betwen widths and atomic parameters Z and I-1 (where Z is the atomic number and I the ionization energy for the upper level) similar to the empirical dependence. On the other hand, analyzing the experimental results for the electron density N > 10(17) CM-3, We Show that there exists an empirical dependence between the width (w) and N given by w is-proportional-to N4/5. In both cases (theoretical and empirical), the atomic number and the inverse of the ionization potential, are relevant atomic parameters to describe linewidths. These can be represented by the empirical expression z1/2W = AI-(3.0+/-0.1).