Fast Recombination of Free Radicals in Solution and Microviscosity
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis is very nice and useful review. I reccommend it for publication in the Journal as it is.
The main question of this review concerns the proper description of diffusion-controlled reactions in terms of how the rate constant of a diffusion-controlled reaction is related to the viscosity of the solvent. It is shown that the experiment can significantly deviate from the dependence predicted by the known Stokes-Enstein formula for the diffusion coefficient in the rate constant. The concepts of so-called microviscosity are considered for a correct description of the experiment. This review, brings together and systematizes publications and results on diffusion-controlled radical recombination and the concept of microviscosity.
Different concepts of microviscosity as well as experimental direct measurement of the diffusion coefficient are discussed in this review. The review deals with diffusion-controlled recombination of radicals and contains many interesting points, such as the fact that the diffusion coefficient of a radical is approximately equal to the diffusion coefficient of the parent molecule (from which this radical was formed). I was very impressed by Fig. 2 showing the universal dependence of the cellular effect on the microviscosity of the stable precursor. Figures and tables are clear, I think it would be possible to improve the quality of Fig. 1 if possible (if the numerical values of the data presented in the figure are preserved). Conclusions are consistent with the experimental evidence and theoretical descriptions using microviscosity approach. References are relevant.
Author Response
Reply to Reviewer 1 comments
I am very pleased that the Reviewer concluded “This is very nice and useful review. I reccommend it for publication in the Journal as it is.”
The two Figures in this review article are copied from the journal's publications with minor improvements. Assuming the manuscript is accepted I will ask for technical help.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments and Suggestions for AuthorsDear Author,
this manuscript reports a review study about the recombination of radicals in solutions. Below are questions and remarks that should be corrected before the manuscript could be consider for publication in Physchem:
1. Explain the symbols in the equation (5), (6) and (7)
2. How did you get the equation (6), the substitution (5) to (2) is unclear
3. Can you explain exactly, what the purpose of the work was? In my opinion the purpose in line 61 is not enough. It should be correlated with section Conclusion.
4. Line 64-add the unit of η
5. Can you explain what is k1?What is the unit of 2k1; what means M-1.s-1 (line 76)
6. Can you explain F (line 78)?
7. Page 3, at the bottom, add the units of η
8. Line 110, use × or · instead of .
9. Figure 2. Explain, what the meaning of the yellow dots, red dots, blue triangles etc.
10. Table 1. What is in column 5 from the left?
11. Section „Conclusion” is too long.
12. Literature is rather old, only 15 articles from the last 10 years, the rest are older than 10 years
13. Figures should be prepared using the dedicated application.
Author Response
Reply to the Review 2 Comments
I am grateful to the Reviewer for the critical comments. I agree with most of them and made the proper revision. The references to line numbers below correspond to the revised manuscript. The revised pieces of text in the revised manuscript are highlighted in yellow in the revised manuscript.
I copied below all the Reviewer’s text as I got it.
The Reviewer’s general address. Dear Author,
this manuscript reports a review study about the recombination of radicals in solutions. Below are questions and remarks that should be corrected before the manuscript could be consider for publication in Physchem:
The Reviewer’s comment.
- Explain the symbols in the equation (5), (6) and (7)
The author’s reply. Done. See lines 57,58. Symbols used in eq. (5) are explained below eq. (5).
The Reviewer’s comment.
- How did you get the equation (6), the substitution (5) to (2) is unclear
The author’s reply. It is simple arithmetic. It was done for the first time by P. Debye in 1943 and has been widely used since then. In particular, it is explained in the textbook, ref. [1].
The Reviewer’s comment.
- Can you explain exactly, what the purpose of the work was? In my opinion the purpose in line 61 is not enough. It should be correlated with section Conclusion.
The author’s reply. I agree. It was specified. See lines 63 and 64. The Conclusion section has been changed and abridged.
The Reviewer’s comment.
- Line 64-add the unit of η
The author’s reply. Done. See the line 67.
The Reviewer’s comment.
- Can you explain what is k1?What is the unit of 2k1; what means M-1.s-1(line 76)
The author’s reply. These are the basics of chemical kinetics, see ref. [1]. The rate constant (k) of bimolecular reaction in solution is usually presented in M-1.s-1. The value 2k is used for identical reagents, see eq. (1).
The Reviewer’s comment.
- Can you explain F (line 78)?
The author’s reply. When a depends upon b, it is common to write a=F(b) or a=f(b). a is a function of b. (I leave this line 81 for the editors).
The Reviewer’s comment.
- Page 3, at the bottom, add the units of η
The author’s reply. Done. See footnote 2 on p. 3.
The Reviewer’s comment.
- Line 110, use × or · instead of .
The author’s reply. Done. See line 112.
The Reviewer’s comment.
- Figure 2. Explain, what the meaning of the yellow dots, red dots, blue triangles etc.
The author’s reply. They mean nothing special in the context of this manuscript. It is stated in the caption See for details [19]. I will ask the technical editors to have the Figure in black and white.
The Reviewer’s comment.
- Table 1. What is in column 5 from the left?
The author’s reply. It was a typo. Corrected, see Table 1, line 283.
The Reviewer’s comment.
- Section „Conclusion” is too long.
The author’s reply. I agree. Abridged.
The Reviewer’s comment.
- Literature is rather old, only 15 articles from the last 10 years, the rest are older than 10 years
The author’s reply. I agree. I had to mention Stokes-Einstein eq. (1905), Debye eq. (1943) without references. Old does not mean bad. I attracted attention to valuable in the author’s opinion, publications. Ten publications are dated 2024 (ref. 9,22-24, 29, 31, 33, 40, 41, 43).
The Reviewer’s comment.
- Figures should be prepared using the dedicated application.’
The author’s reply. The two Figures in this review article are copied from the journal's publications with minor improvements. Assuming the manuscript is accepted I will ask for technical help.
.
The author’s reply. I agree. English was additionally corrected by a native speaker, see the revised manuscript.
The Reviewer’s comment. Abstract. 1. It would be helpful to clarify the significance of the differences between 'microviscosity' and shear viscosity, particularly in non-Newtonian liquids.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsDear Editor, Dear Author,
the work was improved. I acccept it in this form.
