Transitional Strength under Plasma: Precise Estimations of Astrophysically Relevant Electromagnetic Transitions of Ar7+, Kr7+, Xe7+, and Rn7+ under Plasma Atmosphere
Round 1
Reviewer 1 Report
This article provides a useful computation of the atomic structure of fundamental interest using a rigorous methodology. The results are clearly presented with a clear and concise structure.
Overall I recommend the publication of this article in Atom, though I do feel that it could further improve in the following aspects
- The manuscript could be improved by specifying the laboratory or astrophysical conditions, such as ionic density or temperature ranges, under which these plasma screened atomic data are applicable.
- Authors could include an average systematic error of RCC method on oscillator strength comparing to the error of DF and others.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
This manuscript presents a comprehensive study of spectroscopic properties of Ar7+, Kr7+, Xe7+, and Rn7+ ions in both presence and absence of a plasma environment. The authors used Relativistic Coupled Cluster (RCC) to determine excitation energies, transition probabilities, oscillator strengths, and lifetimes, for a range of allowed and forbidden transitions. They compared their results with previous theoretical and experimental data and found good agreement. In addition, the authors investigated the effect of Debye screening lengths and ionization potential depression values on the spectroscopic properties of these ions. Overall, the manuscript is well-written, and the methodology and results are presented clearly. Nevertheless, there are still some concerns that need to be addressed before the manuscript can be accepted.
First, the authors should discuss the advantages and limitations of relativistic coupled-cluster theory compared to other methods, such as MBPT and/or MCDHF, for studying low-charged many-electron ions. They should also provide more background on the importance of these ions in astrophysical plasmas, and why previous studies were inadequate and required new calculations.
Second, the authors should provide more information on the error estimates of their theoretical values, including how correlation and higher-order terms affect their accuracy. It would also be useful to know which relativistic and QED effects are included in their calculations. On page 7, the authors state that relativistic effects have a significant impact on the spectroscopic properties of Xe and Rn ions. They further stated that "it is necessary to perform exhaustive relativistic ab initio correlation calculations for them, and our calculations mitigate exactly this requirement" The authors should consider elaborating on this sentence and explaining how their approach mitigate? Also, the authors estimate that QED effects contribute at most 2% to their results, but more detail is needed on how they arrived at this estimate, given that the QED effects were not included in their calculations. On page 8, clarification of whether this quoted maximum uncertainty applies to wavelengths or transition rates would also be helpful. Also while the authors state that NIST estimations are considered to have the best accuracy, it should be noted that having the best available data does not always translate to having the best accuracy.
Third, the authors mention that they have found an overall good agreement between their results and other theoretical and experimental data available in the literature. However, it would be helpful if the authors could provide more quantitative comparisons with previous results. A figure, rather than just a table, showing experimental values and their errors alongside the authors' own calculated values would be useful.
Finally, the conclusion section should succinctly summarize the results and provide insight into their application in other areas. In the discussion section, the authors mention the possibility of using optical transitions for laser spectroscopy. This sentence seems very vague. Could the authors explain exactly what they are proposing? In the same way, how can the ionization potential depression and the Debye screening data be useful? Could the authors give an example of a plasma diagnostics application for high-density plasmas produced in the laboratory, where their data might be of use?
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The authors present much detailed calculated results on the transition strengths of Ar 7+, Kr 7+, Xe 7+ and Rn 7+ ions, in which plasma effect with Debye model has been accounted. The theoretical calculations are also compared with experimental results and other calculations. This work can benefit for astrophysical and astronomical observations to distinguish the species and estimate the abundance of the ions in the stellar chemical composition. It sounds and can be published with one minor modification,
In paragraph 2 page 3, it’s better to give the definitions of the symbols in “Dirac-Coulomb Hamiltonian H” expression, and delete “Here standard notations are used for all the variables.”.
Author Response
Please see the attached file
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
I would like to start by emphasizing the effort that we, as referees, put into reviewing manuscripts and providing constructive feedback to help authors improve their work. It is important for authors to understand that if a referee finds certain parts of the manuscript difficult to understand, there may be many readers who will struggle with the same issues regarding what you are proposing.
For instance, with respect to laser spectroscopy, authors mentioned at two different places that
"It is found that 5p1/2 - 4 f5/2 of Kr7+ and 5p1/2 - 5p3/2 of Xe7+ emit orange and green lights, respectively, which can be used in laser spectroscopy" and
"a few transitions, such as 4d3/2 − 4 f5/2, 4d5/2 − 4 f5/2 and 4d5/2 − 4 f7/2 of Ar7+, 5p1/2 − 4 f5/2 of Kr7+ and 5p1/2 − 5p3/2 of Xe7+ emit the visible light which can have application in laser spectroscopy."
Now, I am curious to learn more about the kind of experiment authors are proposing for using these transitions in laser spectroscopy. While it is true that they are in the optical range and can be accessed easily via "optical laser spectroscopy," why should experimentalists measure these transitions? Is it simply because these transitions fall within their optical laser wavelength range, or is there more to it? Are you proposing to use these transitions for laser cooling and trapping? If so, please provide an elaborate scheme for the proposed experiment. Otherwise, such statements may be perceived as imprecise/vague/ambiguous.
Similarly, the authors mentioned in the manuscript that "Our presented transition line parameters of Rn7+ may help the astronomer identify the ion's unknown lines. To the best of our knowledge, some of the oscillator strengths of allowed transitions and most of the transition rates of the forbidden transitions are reported here for the first time in the literature." While this statement is significant, it raises questions about which specific Rn7+ transition is strong enough to be observed in astronomical observations, especially considering the unknown abundance of Rn in stellar objects and atmospheres. Therefore, I requested information on the practical applications of the new and improved theoretical data in astrophysics or high energy density plasmas. If the new calculations are only marginally better than the previous ones, then the plasma modeling community have no incentive to update their existing models to integrate the presented new data. Therefore, it is essential to differentiate any new study and its practical significance.
Despite the issues I have highlighted above and in my previous report, I still recommend the manuscript for publication as the calculations are new and can be valuable. Ultimately, I defer to the editor's judgment on whether changes are needed.
At the end, as a referee, reader, and not someone directly working on RCC calculations, I hope the authors understand that my feedback is aimed at improving the manuscript's readability for a wider audience of scientists beyond the authors' own group and collaborators.
Author Response
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Author Response File: Author Response.pdf
