1 Introduction

Potassium lines are present in Solar (Moore et al. 1966) and stellar spectra (Merrill 1956). For example potassium has been found in SN 1987 A ejecta (Trimble 1991). Potassium is a product of alpha processes - neutron capture on slow time scale, and the data on the spectral line broadening parameters of potassium in various ionization stages are of interest for modelling subphotospheric layers (Seaton 1987). Such data are as well of interest for the fusion plasmas and laser-produced plasmas research and for the investigation of soft X-ray lasers (see e.g. Griem & Moreno 1990; Fill & Schöning 1994).

This paper is the twenty second of a series devoted to the research of Stark broadening parameters of spectral lines of multicharged ions (see Dimitrijevic & Sahal-Bréchot 1995 and references therein, as well as Dimitrijevic & Sahal-Bréchot 1996a,b, 1997, 1998a-f). In accordance with our project (see e.g. Dimitrijevic 1996) to make available to astrophysicists and physicists an as large as possible set of reliable semiclassical Stark broadening data needed for the investigation, diagnostics and modeling of various plasmas in astrophysics, physics and technology (see e.g. Dimitrijevic & Sahal-Bréchot 1998f), we have calculated within the semiclassical-perturbation formalism (Sahal-Bréchot 1969a,b), electron-, proton-, and He III-impact line widths and shifts for 4 K VIII and 30 K IX multiplets.