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Peer-Review Record

Theoretical Spectra of Lanthanides for Kilonovae Events: Ho I-III, Er I-IV, Tm I-V, Yb I-VI, Lu I-VII

by Sultana N. Nahar
Reviewer 1: Anonymous
Reviewer 2: Anonymous
Reviewer 3: Anonymous
Submission received: 22 November 2023 / Revised: 13 March 2024 / Accepted: 18 March 2024 / Published: 17 April 2024
(This article belongs to the Special Issue Photoionization of Atoms)

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The present work concerns large-scale computations of atomic data that could be useful to study the electromagnetic emissions recorded in the context of kilonovae events.

The title and the abstract of this manuscript are sufficiently clear.

Atomic data of some low-charged lanthanide ions useful to evaluate spectra in various wavelength domains, from X-ray to infrared, have been computed using the SuperStructure atomic structure code.
The SuperStructure code is briefly presented (Eij and the energy unit must be defined). The sentence (line 101-104 page 4) “Electron are treated…Maxwellian distribution” could be suppressed and could be replaced by a sentence concerning the scaling parameters applying to the TFDA potential.

The photo-absorption cross section is either written \sigma or \sigma_{PI}. A consistent definition must be used.

Electron correlation effects are very important for high-Z elements. Such effects can be taking into account performing a multi-configuration expansion of the atomic wave-functions. In the present study, the configuration basis used for each ionic stage is quite small. What is the impact of these reduced configuration samplings on the atomic data accuracy?

Why the configuration sampling is not the same along an iso-electronic sequence (for example TmV and YbVI)?

Table 1 should be carefully checked. For example, the number of filled orbitals of HoII is not correctly defined, the configuration labeled (2) is wrong, the configurations labeled (2) and (4) of TmIV are the same, some configuration labels of YbIII are missing, the configuration labeled (1) of YbVI is wrong, from YbVI to LuVII the 5d orbital needs parentheses, the configuration labeled (4) of LuVII is wrong.

Regarding Figure 1, the photon energy unit must be the same for both graphs in order to objectively judge “very good agreement”.

Page 11, line 284 : the notion of “length of the orbital wave-functions” should be replaced by “the spatial extension of the orbital wave-functions”

To conclude, the present manuscript is not suitable for publication. The manuscript need to be revised according to the questions and remarks.


Author Response

Please find the attached file for detailed responses.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The observations of a neutron-star merger in 2017 with the detection of gravitational waves and of associated electromagnetic radiation together with the interpretation of the results has stimulated renewed interest in the radiative properties of the lanthanide atoms and ions. The lack of atomic data motivated the present investigation in which energies of excited states and radiative decay rates were calculated. Cross sections for the absorption of photons in a wide range of wavelengths were determined for 25 lanthanide atoms and low-charged ions. After careful consideration of my remarks the paper will be worth being published in ATOMS.

The electronic structure of lanthanides is very complex. Hence, theoretical calculations are difficult and considerable uncertainties have to be expected. Comparison of results of the present investigation with sparsely available data support the validity of the present calculations, though, with the possibility of substantial deviations. Assessment of possible uncertainties is desirable and important. I wonder, how the present results compare with the data obtained recently by Irvine et al., JQSRT 297, 108486 (2023).

The present manuscript has substantial deficiencies in English grammar which sometimes brings it to the brink of not being understandable. In the interest of future readers and the quality standards of ATOMS, I recommend careful language editing before printing.

There is no clear statement about the way the photoabsorption cross sections are plotted and the associated tables are not yet accessible (the author promises to provide this material on her NORAD platform). I am afraid that the Lorentzian widths of the absorption lines are not considered. Eq. 5 gives a cross section without a frequency dependence. What is the meaning of that without providing a frequency-distribution function? Are the cross sections binned in given frequency intervals? In that case the unit should be Mb eV rather than just Mb. What would be the prescription for comparing the cross sections with an experiment which always has a frequency spread?

I will now go through the manuscript step by step and point out misprints, inconsistencies and other issues.

Table 2: the headline of the table gives 2J+1 as an entry, however, the real entries seem to be just 2J

Table 3; 2nd line of the caption:    …Ni and Nj…

              2nd line of the caption:    …SLpCi…

              Entries in the table: the 2nd, 4th, and 6th line are duplicates of the 1st, 3rd, and 5th line

Paragraph starting in line 171: Obaid et al. did not measure the photoabsorption of Ho II. Apparently, they measured photofragmentation of neutral Ho3N@C80 observing the production of Ho+ which is certainly not immediately comparable with the absorption spectrum of Ho II (see Fig. 1).  Comparison of the present results for Ho I with the photoabsorption cross section of solid Ho would make more sense.

Misprints occur regularly when the unit Angstrom is followed by “and” or “The” or “with” (see e.g. lines 243, 315)

Line 248: the wavelength range is given with misprints

Line 299: specify n and l here

Line 303:    …bump…

Line 310: an example for problems with English grammar  … There is no … levels…

Lines 317/318: the meaning of this sentence is not clear; 1.1-3 appears to be a misprint; unit?

Table 4 caption 1st line:    …Ho, Er, Tm, Yb, Lu…

one of the entries is given as J on page 14; in the         continuation of Table 4 (not Table 2) on the next several   pages the headline says “2J”, but the   
  entries appear to be still J

 

Use consistent legends in the figures: No of transitions…, Number of transitions…, # transitions, # of transitions

Fig 10:  The feature at about 31000 Angstrom looks broad. This is probably an artifact of the way how the “cross sections” are plotted (see my remarks on line widths).

Fig. 16 caption: what is “range of E to EUV”?

Line 402: …Penkin…

Fig. 22: another obvious problem with the way of how “cross sections” are plotted

Line 423: this sounds like a photon looses energy when passing an absorber

Lines 431 and 433: I would hesitate to speak of “high precision” and “overall good agreement” in the context of the present work.

Lines 438 and 439: just a false statement

Comments on the Quality of English Language

The present manuscript has substantial deficiencies in English grammar which sometimes brings it to the brink of not being understandable. In the interest of future readers and the quality standards of ATOMS, I recommend careful language editing before printing.

Author Response

Please see the attached file for detailed responses.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Review on paper Theoretical spectra of lanthanides for kilonovae events: Ho I-III, Er I-IV, Tm I-V, Yb I-VI, Lu I-VII”

Line 61: Radzute should be “Radžiūtė“

Line 450: References aren’t formatted according to Journal requirements.

Line 86: e,g, --e.g.

4.1 subsection is a bit unclear. How many files are given in the “NORAD-Atomic-Data database”? How many tables are given in each file?

In the caption of the table 3 „Ni and Ni“ should be „Ni and Nj“ (i--→j).

 

In the paper 10 energy levels were selected for each ion to analyze the accuracy. Such set of levels is too small to extend the accuracy for the rest of the levels. For example, 1629 levels were computed for Ho I and only 10 levels were compared, when in the NIST there are many levels with full spectroscopic identification for comparison and accuracy investigation.

Almost all levels of ground configuration (4f11.6s2 (1)) have pure LS coupling. Second configuration (4f10 6s2 6p (2) odd) indeed has stronger mixing between different terms, but still there is a lot of levels with full identification.

Third configuration (4f10 6s2 5d (3) even) has strong mixing with 4f11 6s 6p configuration. For example, level with E=0.1472080 Ry consists of 62 % 4f10.5d.6s2 configuration and 38 % 4f11.6s.6p configuration. This rises a new problem, because 4f11.6s.6p configuration is not included in the computation, therefore the energy levels without it can not be accurate. The following data of transitions and photo-absorption cross sections will be even more unreliable.

Comparison based only on parity (ignoring the configurations, terms and J values) is not correct. J is a good quantum number, therefore it can not be ignored. In addition, energy level with a value of 0.1031765 Ry is identified as 4f10(5I8)5d5/26s2 (8,5/2) J=21/2 (full spectroscopic identification) in the NIST and it is compared with a level identified as 4f116s2 (odd configuration) 4M J=17/2 (0.13881 Ry). In this case, the parity is also ignored.

When Ho I (10 levels) is compared with NIST, differences vary from 14% up to 47%, 30% in average, therefore, the agreement with NIST is not very good.

Based on the statements above and that similar situation is visible also in other atoms and ions in the paper, author cannot conclude that “These data are expected to be much more improved in accuracy than those available” (conclusion 2). Only very small part of data is benchmarked with NIST. Therefore, author cannot conclude that “The calculated energies have been benchmarked with the measured values” (conclusion 3.), also that “Comparison shows overall good agreement” (conclusion 3.).

 

Author Response

Please see the attached file for detailed responses.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

 

Regarding the revised manuscript, all my comments have been taken into account. This revised manuscript now deserves publication.

Author Response

Please see the attached file.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Review on the paper Theoretical spectra of lanthanides for kilonovae events: Ho I-III, Er I-IV, Tm I-V, Yb I-VI, Lu I-VII

The comparison of energy levels is incorrect, even if it is described in the article. The comparison cannot ignore the total angular moment, as has been done in several places in the table 4. Erroneous J-values are sometimes found in the NIST database, but this is rare, so a thorough investigation is needed to resolve the error, and a poor level mismatch is not proof of this.  This table should be corrected and the text of the paper should be corrected accordingly.

Please provide energy estimation in percentages in conclusion 3.

Author Response

Please see the attached file

Author Response File: Author Response.pdf

Round 3

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript was sufficiently improved to be accepted for publication.

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