Summaries of the semiclassical perturbation formalism
(Sahal-Bréchot
1969a,b) and of the modified semiempirical formalism
(Dimitrijevic &
Konjevic 1980) are given in
Dimitrijevic & Sahal-Bréchot (1995) and
Popovic &
Dimitrijevic (1996b) and will not be repeated here.
The atomic energy levels needed for calculations were taken
from Bashkin & Stoner (1987) for Mn II,
Moore (1971) for Mn III,
Ryabtsev
& Wyart (1987) and
Isberg & Litzén (1986) for Ga III,
Sugar &
Musgrove (1993) for Ge III, and in
Ryabtsev & Wyart (1987) and
Sugar
& Musgrove (1993) for Ge IV. Oscillator strengths have been
calculated by using the method of Bates 
Damgaard (1949) and
the tables of Oertel Shomo (1968). For higher levels, the
method described by Van Regemorter et al. (1979) has been used.
Results obtained within the modified semiempirical approach - MSE
(Dimitrijevic & Konjevic 1980) for
electron - impact line widths and shifts for
16 Mn II, 3 Mn III, 10 Ga III, 8 Ge
III and 14 Ge IV multiplets
as a function of temperature are presented in Tables 1 - 3 (accessibles
only in electronic form). The calculations were performed for the
perturber density of 
.
Within the used approach, results for electron-impact broadening
parameters are linear with electron density.
For three lines of Ge IV it is possible to calculate Stark broadening
parameters within the semiclassical perturbation approach
(Sahal-Bréchot 1969a,b).
For
electron-, proton-, and
He III-impact line widths and shifts for 3 Ge IV
multiplets
for the perturber densities of 
and temperatures 
,
are shown in
Table 4 (accessible only in electronic form).
For electron densities lower than tabulated, a linear interpolation
with density is sufficient.
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 0.1 < NV 
are denoted by an asterisk.
For higher densities, when the impact approximation is not valid, the
ion
broadening contribution may be estimated by using
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 decreases when broadening by ion
interactions becomes important. As an illustration, in Fig. 1 (click here). we have
compared Stark widths calculated by using the semiclassical, MSE, simplified
MSE and Griem's semiempirical appraoch.
Figure 1: Stark full widths for 
transition of Ge IV calculated by using different approximations, as functions
of temperature. The electron density is
In the case of these ions there is not measured Stark broadening parameters.
For Mn II 
transition Dimitrijevic (1982) performed calculations
by using the MSE, Griem's semiempirical approach - SE (Griem 1968) and
semiclassical approach of Griem (see Jones et al. 1971; Griem 1974). Since
these data complete MSE results for Mn II they are shown here in Table 5 (click here),
together with semiempirical and semiclassical results. The MSE results are in
good agreement with more sophisticated semiclassical calculations. For Ga III
multiplet calculations by using the MSE and the SE approach as
well as calculations by using approximate semiclassical method (Griem
1974) and
the modification of this method (Dimitrijevic & Konjevic 1980) were
performed by Dimitrijevic & Artru (1986). For this multiplet calculations
within the SE approach are given in Puric et al. (1978) as well. Results
according to the approximate semiclassical method are slightly larger than MSE
results and results obtained by the modification of approximate semiclassical
method which are in good agreement.
Also, for Mn II 
multiplet, width and shift estimated on the
basis of Stark broadening parameters dependence on ionized potential from the
lower level of the corresponding transition exist as well (Lakicevic 1983).
For an electron density of and an electron temperature of
20000 K, Lakicevic obtains 
= 0.008 nm and 
= 0.0036 nm, while our
results are 
= 0.0041 nm and 
= 0.00093 nm.
We hope that Stark broadening data presented here will be of interest for space spectroscopy and for chemically peculiar star research as well as for laboratory plasma spectroscopy. Experimental data for considered ion lines will be of interest for the discussion and developement of Stark broadening theory for heavier emitters with more complex spectra.
Acknowledgements
This work is a part of the project "Astrometrical, Astrodynamical and Astrophysical Investigations", supported by Ministry of Science and Technology of Serbia.