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).
The complete
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.

*Acknowledgements*

This work is a part of the project "Astrometrical, Astrodynamical and Astrophysical Investigations", supported by Ministry of Science and Technology of Serbia.