Stark Broadening of N VI Spectral Lines
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe MS is addressed to calculations of the Stark broadening parameters, line widths and shifts, for 15 N VI multiplets by various impact partners. This information is highly needed for applications in different cases, for example, for NLTE modelling of stellar atmospheres, and hence, should be welcomed by different atomic and molecular data bases and different groups of astrophysicists. The paper starts with Introduction, which provides the readers by the complete review of the field of line broadening parameters, line wisths and shifts. The main interest in the paper is the collision processes involving ions, first of all, the nitrogen ions collided by electrons, protons, helium ions, etc. The calculations are performed by the semiemphirical perturbation method for high temperatures, from 50'000 till 2'000'000 K. It is worth emphasizing that in the end of the paper the authors indicate that in some cases their results deviate from other data. And this comment may open a way to find possible limitations of the perturbation theory due to significant effect of the so-called electron translation effect at high collision energies, the effect is fundamental but usually neglected. It would be interesting how inclusion of this phenomena into consideration affects the calculated inelastic cross sections. This remark is rather addressed a possible future work of the authors, then a comment on the present work.
Finally, I recommend this MS for publication in the present form.
Comments on the Quality of English LanguageMinor corrections.
Author Response
We are very grateful to reviewer for careful reading and very useful and positive comments.
Reviewer 2 Report
Comments and Suggestions for AuthorsThis paper describing calculations of Stark broadening parameters is clearly written. I have not detected any fundamental causes for concern. Here are some minor suggestions.
1) Abstract. Consider writing "spectral class DO white dwarfs" instead of just "DO white dwarfs".
2) Line 36. Consider spelling out the X-ray Multi-Mirror Mission, and/or adding a bibliographic reference regarding the XMM-Newton mission.
3) Spell out the non-local thermodynamic equilibrium.
4) Conclusions "the bor nitride" --> "the boron nitride"
Comments on the Quality of English Language
The English is fully understandable. Perhaps a minor editing would be beneficial.
Author Response
We are very grateful to reviewer for the useful remarks and for his efforts to improve our article.
Our answers are to his remarks are the following:
1) Abstract. Consider writing "spectral class DO white dwarfs" instead of just "DO white dwarfs".
Corrected
2) Line 36. Consider spelling out the X-ray Multi-Mirror Mission, and/or adding a bibliographic reference regarding the XMM-Newton mission.
Instead off " XMM-Newton" now is "XMM-Newton (XMM - X-ray Multi-Mirror Mission \cite{Ja01})"
In references we added:
Jansen, F.; Lumb, D.; Altieri, B.; Clavel, J.; Ehle, M.; Erd, C.; Gabriel, C.; Guainazzi, M.; Gondoin, P.; Much, R.; et al. XMM-Newton observatory. I. The spacecraft and operations.
{\it A\&A} {\bf 2001}, {\it 365}, L1--L6.
3) Spell out the non-local thermodynamic equilibrium.
On first appearance, "NLTE" is changed with "a non-local thermodynamic equilibrium (NLTE)"
4) Conclusions "the bor nitride" --> "the boron nitride"
Corrected
Reviewer 3 Report
Comments and Suggestions for AuthorsThe manuscript entitled “Stark Broadening of N VI Spectral Lines” by Dimitrijevic et al. presents calculations of the Stark broadening parameters, including line widths and shifts, for 15 N VI multiplets using semiclassical perturbation theory. The perturbers considered are electrons, protons and He III ions and B III, B IV, B V and B VI ions. These line broadening parameters should be useful for white dwarf atmospheres modelling, abundance determination, analysis and synthesis of their spectra, and for proton-boron fusion investigations. Semiclassical perturbation theory has been developed for a long time and has been applied in astrophysics and plasma physics. The manuscript is suitable for publication in Universe if the authors can reasonably address the following specific points.
1.In Tables 1-4, do the electron temperature and density refer to the plasma condition of N plasmas? If so, what is the proton density? In the calculations of Stark width and shift, the proton density is needed and should be specified.
2.The authors mentioned the previous work [32,34] to compare with their Stark broadening calculations of Stark widths for four N VI spectral lines. They found that the values in these two references are too small in comparison with their calculations. The physical reason for such a large discrepancy should be discussed if they cannot find other evidences to support their results.
3. Minor issues:
P1, line 24, “Nitrogen lines are widely present in stellar spectra (see e.g. [9–14,16,17]).”, reference [15] is not correctly ordered. (See also P2, line 66, “are observed in the high-resolution X-ray spectra of nova RS Ophiuchi [15].”
P2, line 62, “may occurs an additional” to be “may occur an additional”.
P3, line 96, “When laser intensities I>= 1020 W/cm^2” may be “When laser intensities I>= 10^{20} W/cm^2”.
Comments for author File: 
Comments.pdf
Author Response
We are very grateful to reviewer for the useful remarks and for his efforts to improve our article.
Our answers are to his remarks are the following:
1.In Tables 1-4, do the electron temperature and density refer to the plasma condition of N plasmas? If so, what is the proton density? In the calculations of Stark width and shift, the proton density is needed and should be specified.
In the captions of Tables 1-4, "an electron density" is replaced by "a perturber density". Thank you very much for drawing our attention to this.
2.The authors mentioned the previous work [32,34] to compare with their Stark broadening calculations of Stark widths for four N VI spectral lines. They found that the values in these two references are too small in comparison with their calculations. The physical reason for such a large discrepancy should be discussed if they cannot find other evidences to support their results.
At the end of Section 3, we added the sentence:
For example in the formulation of the empirical part of the modified semiempirical theory \cite{Di80},
empirical data for cross sections of highly charged ions should be taken into account due to the increasing influence of relativistic effects.
3. Minor issues:
P1, line 24, “Nitrogen lines are widely present in stellar spectra (see e.g. [9–14,16,17]).”, reference [15] is not correctly ordered. (See also P2, line 66, “are observed in the high-resolution X-ray spectra of nova RS Ophiuchi [15].”
Corrected
P2, line 62, “may occurs an additional” to be “may occur an additional”.
Corrected
P3, line 96, “When laser intensities I>= 1020 W/cm^2” may be “When laser intensities I>= 10^{20} W/cm^2”.
Corrected
