The semiclassical perturbation formalism and the relevant computer code (Sahal-Bréchot 1969a,b) used here, have been modernized, updated and optimized several times (Sahal-Bréchot 1974; Fleurier et al. 1977; Dimitrijevic & Sahal-Bréchot 1984; Dimitrijevic et al. 1991; Dimitrijevic & Sahal-Bréchot 1996b). The used formalism has been reviewed e.g. in Dimitrijevic & Sahal-Bréchot (1996c) and Dimitrijevic (1996). The atomic energy levels of Ca IX and Ca X needed for calculations have been taken from Bashkin & Stoner (1975). The oscillator strengths have been calculated within the Coulomb approximation (Bates & Damgaard 1949, and the tables of Oertel & Shomo 1968). For higher levels, the method of Van Regemorter et al. (1979) has been used.
Our results for electron-, proton-, and
He III-impact line widths and shifts for 4 Ca IX multiplets
for perturber densities
and 48 Ca X multiplets
for perturber densities , for
the electron temperatures ,
are shown in Table 1 (accessible only in electronic form).
set of data is given for the
perturber density of for
Ca IX and for Ca X. For lower tabulated perturber densities, only data for higher transitions, needed for better interpolation are given. Stark broadening parameters for densities lower than tabulated, are linear with perturber density. We also specify a parameter c (Dimitrijevic & Sahal-Bréchot 1984), which gives an estimate for the maximum perturber density for which the line may be treated as isolated when it is divided by the corresponding full width at half maximum. For each value given in Table 1, the collision volume (V) multiplied by the perturber density (N) is much less than one and the impact approximation is valid (Sahal-Bréchot 1969a,b). Values for NV > 0.5 are not given and values for are denoted by an asterisk. When the impact approximation is not valid, the ion broadening contribution may be estimated by using the quasistatic approach (Sahal-Bréchot 1991 or Griem 1974). In the region between where neither of these two approximations is valid, a unified type theory should be used. For example in Barnard et al. (1974), simple analytical formulas for such a case are given. The accuracy of the results obtained decreases when broadening by ion interactions becomes important.
We hope the presented results will be useful for the modelling and research of subphotospheric layers and that considerations of radiation transfer, as well as for laboratory plasma investigations. Besides the theoretical data, reliable experimental data will be of significance for further development and refinement of the Stark broadening theory for multicharged ion lineshapes, as well as for the investigation of regularities and systematic trends of Stark broadening parameters along isoelectronic sequences.
This work is a part of the project "Astrometrical, Astrodynamical and Astrophysical Investigations", supported by Ministry of Science and Technology of Serbia.