You may wish to consult the following two review articles:

[1] J Walker, Rep. Prog. Phys. 42, 108 (1979).

See in particular Sec. 3.2.1.2, p. 1619.

[2] AT Collins, Diamond and Related Materials 8, 1455 (1999).

Dear Farid,

thanks for the links, but I need a substantiation of the defect model B1 as N4V - a vacancy surrounded by four nitrogen atoms. Who proposed such a model and scientific justification

Vasily

Dear Vasily, you are welcome.

If you consider the reviews that I have cited, both give the relevant references -- from the earliest time to the times of writing the reviews. The review by Walker very explicitly concludes that the model of the B1 defect as a vacancy surrounded by four nitrogen atoms is far from settled. Collins in his review cites Evans and Qi [1] (his Ref. [12]) for aggregates of nitrogen in diamond, so perhaps you will find the answer to your question in the work by Evans and Qi [1], which I am not familiar with.

[1]Article The Kinetics of the Aggregation of Nitrogen Atoms in Diamond

Dear Farid,

Thanks for the links to the reports. These reports are known to me, like many others.

In Walker's review, there is no mention of the B1 model as a vacancy surrounded by four nitrogen.

Evans' work contains only the assumption that two diatomic defects due to aggregation give rise to a four-atom defect. This is not convincing.

I'm looking for a publication with scientific justifications for this model. Really they are not present?

Vasily

Dear Vasily,

You are welcome.

Walker does discuss the B1 model (as I wrote in my very first comment on this page, the relevant section in Walker's review is Sec. 3.2.1.2, p. 1619, of his review). In my second comment on this page, I did explicitly mention that 'Walker very explicitly concludes that the model of the B1 defect as a vacancy surrounded by four nitrogen atoms is far from settled'. Your latest response suggests as though I had made a comment contrary to yours. On this entire page I have made not a single statement for or against the model.

If you consider the way you have formulated your main question on this page, it is not about whether the model of a vacancy in diamond surrounded by four nitrogen atom is a good model for the B1 defect, but it is about the original reference; the question does not ask any judgement on the model (you have written: 'Can someone point to the source with the scientific justification for such a model? ' You have clearly not asked for an expert view as to the viability of the model). Thus, far from advocating the model, or even rejecting it, I merely suggested that the required original source should be sought primarily in Walker's review and secondarily in the more recent review by Collins. I maintain that the original source is cited by Walker. For instance, in Sec. 3.2.1, page 1617, of his review, Walker presents the entire history of the A, B1 and B2 bands. What is needed is going through these original sources and see who, or which group, has originally explicitly put forward the model (for instance, Walker ascribes the discovery of the A, B1 and B2 bands to Robertson et al., 1934).

Dear Farid.

Thanks for the comment.

In Walker's work quoted by you on page 1621 there is not a word about a vacancy surrounded by four nitrogen atoms. It writes: "The defect model B1 is far from solving" only.

You correctly understood, I am not satisfied with the existing model B1 as a vacancy in the environment of 4 nitrogen and I have an intention to discuss it. You also correctly understood that I do not need an expert opinion on the model. I need a link to the source only.

You advise me to go through these sources and see who or which group originally proposed the model.

Thank you. Since that I started 30 years ago, when I was a student.

Yours faithfully

Vasily

Dear Vasily Pavlovitch! As I know, the first assumption of such the B1 structure is the unpublished work of Loubser and Van Wyk, 1981, Diamond Conference, Reading (from "First-principles theory of nitrogen aggregates in diamond, R. Jones et al., 1992; " Infrared absorption by the B in diamond" Boyd et al, 1995). Clark and Davey in 1983, in "One-phonon infrared absorption in diamond" did not discuss or mention this model : Evans and Qi (1982) only "indicated that the B-centre is probably a more highly aggregated form of nitrogen than the A-centre"

Dear Vasily,

What I wrote was not that Walker explicitly attributes the model to any particular person, but that by digging into his relevant references one might be able to trace the original reference. You did not need to tell me that you started out 30 years ago with the subject, since certainly I had not said anything to the contrary. My remark had solely bearing on the way you have formulated the main question on this page, which merely asks about 'the original source', and not about the reliability or otherwise of the relevant model.

In any case, I see that in the meantime E Vasil'ev has presented the answer that I had independently arrived at (minutes before writing these lines), by consulting the PhD thesis of Matthew W Dale (University of Warwick, 2015) [1] (see the table on page 4 herein); he also gives the reference to the computational work by Jones et al. [2]. Checking on the names Loubser and Van Wyk, I have established that their unpublished work (1981) has been cited in Refs [3,4].

[1] http://wrap.warwick.ac.uk/80044

[2] R Jones, et al., Phil. Mag. Lett. 66, 67 (1992).

[3] PJ Fallon, et al., Phil. Mag. A 72, 21 (1995).

[4] AT Collins, J. Gemm. 27, 341 (2001).

Dear Evgeni,

thank you for the information.

Probably, the authors did not publish the work, because they saw in it significant shortcomings.

Look at the link given by Farid to the thesis. The author of the dissertation of our works obviously did not read.

Vasily

Dear Farid,

Thank you for your attention. You really helped me.

Probably, the N4V model penetrated into the literature from Wikipedia.

Vasily