COLLISION OPERATOR FOR ISOLATED ION LINES IN THE STANDARD STARK-BROADENING THEORY WITH APPLICATIONS TO THE Z-SCALING IN THE LI ISOELECTRONIC SERIES 3P-3S TRANSITION

In this work we review some aspects of the semiclassical dipole impact approximation for isolated ion lines with a view to the questions on Z scaling raised by two recent experimental studies. Some theoretical and practical aspects of line-shape calculations are discussed. Detailed calculations are performed in the semiclassical (dipole) impact approximation for the Li isoelectronic 3P-3S line. Particular emphasis is given to inelasticity effects. In contrast to previous calculations, very good agreement is obtained for the lighter elements of the isoelectronic series. Ion dynamical corrections are also considered and are found to be negligible in the dipole approximation.