## addenda and errata

## Theoretical study of the properties of X-ray diffraction moiré fringes. I. Corrigenda and addenda

^{a}Sakai 5-13-2-A322, Musashino-shi, Tokyo 180-0022, Japan^{*}Correspondence e-mail: j-yoshimura@voice.ocn.ne.jp

Seven corrections are made and several supplementary equations are added to the article by Yoshimura [*Acta Cryst.* (2015), A**71**, 368–381].

Keywords: diffraction moiré fringes; *Pendellösung* oscillation; phase jump; gap phase.

On p. 371, left column, near the top, just after `the index (*i*) = (1, 2) … dispersion surface', the following comment should be added: `the upper sine in equations (5*a*), (5*b*) refers to the case of *i* = 1, and the lower sine to the case of *i* = 2'. On p. 371, right column, near the bottom, just after `the indices (*i*, *j*) = (1, 2) …, respectively', the following comment should be added: `the upper sign in equations (15*a*) to (15*d*) refers to the case of *j* = 1, and the lower sine to the case of *j* = 2'. Equations (14*b*), (14*c*) are incorrect. They must be corrected to

In these corrections, the last terms in the first exponential functions on the right-hand side in the second equations were corrected.

On p. 372, right column, an error is involved in equation (22*a*). It must be corrected to

In this correction, the last term in the second bracket on the right-hand side was corrected. On p. 373, left column, equation (24*b*) is incorrect. It must be corrected to

On p. 376, left column, the description of `*t*_{gap} = 0.024 mm' is incorrect. It must be corrected to `*t*_{gap} = 0.24 mm'. The mentioned errors in equations (14*b*), (14*c*) and (24*b*) do not influence the calculation of equations (20) to (23*b*), since the correct expressions as above were used in deriving them. The mentioned error in equation (22*a)* does not influence the computations of the presented images and graphs in the paper, since the computations were all made correctly using the correct expression as mentioned above; the errors are only in the text.

As a supplement to the previous presentation of the equation for the diffracted – or *G* – wave image intensity in equation (20), the equation for the corresponding transmitted – or *O* – wave image intensity is added as in the following:

with

The numbering of the equations here is continued from the last equation (48) in the original paper (Yoshimura, 2015). and in equation (49) are as given in equations (14*a*), (14*c*), respectively.

Through similar calculations to those written in the right-hand side column on p. 373, the term of interference phase in equation (50) can be reduced to

which is the same as in equation (34) for the *G*-wave image intensity (here, the symbol || denotes the component parallel to the specimen surfaces). In the present case that , part of the first term and the fourth term in equation (50) cancel each other as follows:

The moiré images of the *O*-wave in Figs. 14(*a*) and 14(*b*) and the curves concerned in Figs. 15(*a*) and 15(*b*) were computed using these equations (49), (51*a*)–(52*b*) and (53).

### References

Yoshimura, J. (2015). *Acta Cryst.* A**71**, 368–381. CrossRef IUCr Journals Google Scholar

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