# Re: R 3 m:R in fullprof

```Dear Igoa,

I am touched with your kind reply!!```
```
I agree with your opinions as you told me perfectly, the Z difference bewtween
hexa and rhombo system, and hexagonal system is more reliable results.

That is why I was really confused to refine, and I thought I had to appy the
hexagonal system to refine regardless of rhombohderal phase.

Is it possible to earn different results depending on the choice of axe, even
though it is same structure..?!

Anyways, I am going to send our discussion to the fullprof support team on the
fullprof homepage.

Also, if you feel free and have spare time, you can ask this issue to anyone.

I will share any opinion from the support team as soon as I receive.

Thanks for your expertise again.

Best regards,

Do-Yeon, Kim

============================================

김도연 (Kim Do Yeon)

Pohang Accelerator Laboratory (PAL)

80 Jigokro-127-beongil, Nam-gu, Pohang, Gyeongbuk, 37673 Republic of Korea

E-mail: kdo01...@postech.ac.kr, kdo01...@gmail.com

Tel: +82-054-279-1613, Mobile : +82-010-7350-2858

________________________________
보낸 사람: Fernando Igoa <fer.igoa.1...@gmail.com>
보낸 날짜: 2022년 8월 10일 수요일 오후 7:21
받는 사람: 김도연(에너지환경연구팀) <kdo01...@postech.ac.kr>
제목: Re: R 3 m:R in fullprof

Hello Kim,

Thank you very much for sharing your files.

I took a look at your pcr, I don't see anything wrong in your inputs, so I
tried to break down the problem:

See, the phase fraction (Wj) is calculated as:

Wj = Sj.Vj.ATZj/Sum(i)[Si.Vi.ATZi]

Where Sj is the scale factor, Vj the cell volume and

ATZ = Z.Mw.f^2 / t

Where Z is the number of formula units per cell, Mw the molecular weight, f are
the transformed occupancies I talked you about before (f = occ*M/m with occ =
chemical occupancy, m = site multiplicity and M = general multiplicity).

Your ATZ are coherent, for the Hexagonal system you have 738.7585 and for the
rhombohedral you have 246.2509, that is exactly 3 times smaller, as it should
be from the difference in Z (Z = 1 for R, Z = 3 for H).

Now this factor of 3 is never compensated back as far as I can tell. According
to the equation of Wj, the only way to compensate it, is with the scale factor
Sj, but you have the same scale factor for both phases. I took the liberty to
calculate what would you obtain with a scale factor 3 times larger for BaHfTiO3
and 3 times smaller for the other 2 phases, and indeed the results become much
more similar than to the hexagonal system, still not the same because the scale
factor does not necessarily has to be 3 times larger to accurately compensate
because you have the other 2 scale factor of the other two phases).

Anyway, I think is not you is the program, and I think that this is a question
to take to Rodriguez-Carvajal, if you are interested you can write him yourself
or if you allow me I can write on your behalf as this interests me as well.

In any case, if you are in a hurry, trust the Hexagonal system result, your
pattern is clearly 96 % pure and not 73 %.

Apologies I could not be of further help, if you figure something out also let

Best,

Fernando Igoa
PhD student
Laboratoire Chimie de la Matière Condensée de Paris
Sorbonne Université
4 place Jussieu
75005 PARIS

ORCID: orcid.org/0000-0002-3960-4720<https://orcid.org/0000-0002-3960-4720>
ResearchGate:
researchgate.net/profile/Fernando_Igoa<https://www.researchgate.net/profile/Fernando_Igoa>

El mié, 10 ago 2022 a la(s) 08:14, 김도연(에너지환경연구팀)
(kdo01...@postech.ac.kr<mailto:kdo01...@postech.ac.kr>) escribió:
Dear Igoa,

I really appreciate your contact and reply !!

I attached my pcr files, and you can check my results as I posted.

In details, I am researching the perovskite structure on BaTiO3, and I doped Hf
into Ti site.

While doing refinement, I found that the weight fraction was severe different
depending on the choice of axes.

Just I want to know and check that we can earn different refinement data
depending on the choice of axes.

In addition, if I refine hexagonal system, I have to use the crystal structure
information from standardized crystal structure data in ICSD?

(I attached BaTiO3 rhombohedral phase, ICSD information)

or just something wrong in fullprof program?

Thus, also if you deal with some materials which are the hexagonal structure,
could you try them like me?

Thanks for your kind and expertise,

Best regards,

Do-Yeon, Kim

============================================

김도연 (Kim Do Yeon)

Pohang Accelerator Laboratory (PAL)

80 Jigokro-127-beongil, Nam-gu, Pohang, Gyeongbuk, 37673 Republic of Korea

E-mail: kdo01...@postech.ac.kr<mailto:kdo01...@postech.ac.kr>,
kdo01...@gmail.com<mailto:kdo01...@gmail.com>

Tel: +82-054-279-1613, Mobile : +82-010-7350-2858

________________________________
보낸 사람: Fernando Igoa <fer.igoa.1...@gmail.com<mailto:fer.igoa.1...@gmail.com>>
보낸 날짜: 2022년 8월 10일 수요일 오후 2:48
받는 사람: 김도연(에너지환경연구팀) <kdo01...@postech.ac.kr<mailto:kdo01...@postech.ac.kr>>
참조: rietveld_l@ill.fr<mailto:rietveld_l@ill.fr>
<rietveld_l@ill.fr<mailto:rietveld_l@ill.fr>>
제목: Re: R 3 m:R in fullprof

Dear Kim,

Are you sure you are deleting/adding the atoms generated by the change of
system?

Otherwise did you check if the occupations remain the same for the atoms after
refining in each system? Like the true chemical occupations, not the occupation
number refined in fullprof. Because in fullprof, the refined occupation number
is calculated as the chemical occupancy x site multiplicity. Now this may or
may not be normalised to the multiplicity of the general position of the group
(literally in the manual it says "can be normalised to the multiplicity of the
general position of the group"). So it may be that if this is not normalized,
and you keep the same occupation numbers, this will change your chemical
occupation, hence your weight fraction.

Other than that I'm out of clue, if you could share the pcr file it would be of
use.

Hope it helps, let me know.

Best,

Fernando Igoa
PhD student
Laboratoire Chimie de la Matière Condensée de Paris
Sorbonne Université
4 place Jussieu
75005 PARIS

ORCID: orcid.org/0000-0002-3960-4720<https://orcid.org/0000-0002-3960-4720>
ResearchGate:
researchgate.net/profile/Fernando_Igoa<https://www.researchgate.net/profile/Fernando_Igoa>

El mié, 10 ago 2022 a la(s) 02:29, 김도연(에너지환경연구팀)
(kdo01...@postech.ac.kr<mailto:kdo01...@postech.ac.kr>) escribió:

Hello, all experts

I figured out the excited update in fullprof, which was we can do refine the
primitive cell of rhombohedral group immediately.
(https://www.ill.eu/sites/fullprof/php/FullProf_News_2022.htm#2007)
Fullprof News -
2022<https://www.ill.eu/sites/fullprof/php/FullProf_News_2022.htm#2007>
Full Year 2022----- >> 2 August 2022 : Automatic renumbering of codes used in
linear restraints ----- - If modifications of VARY/FIX commands to refine or
fix some parameters were used, the renumbering of explicit codes used in linear
restraints instructions was not applied.
www.ill.eu<http://www.ill.eu>

My material is R 3 m (#160), and I am trying to refine it using R 3 m:R with
the rhombohedral structure information.

Let me suppose my material is A, the second impurity is B. (my data have only
two phases)

When I refine using R 3 m with the trigonal structure, I earn the weight
fraction A:B=80%:20%

But, when I refine using R 3 m:R with the rhombohedral structure, I earn the
weight fraction A:B=50%:50%.

When I tried both cases, I put all paramteters with same values in the second
impurity like same scale factor, same profile values..

That is why I am getting in the problem on the weight fraction, and I am so
confused..

Thanks,

Do-Yeon, Kim

============================================

김도연 (Kim Do Yeon)

Pohang Accelerator Laboratory (PAL)

80 Jigokro-127-beongil, Nam-gu, Pohang, Gyeongbuk, 37673 Republic of Korea

E-mail: kdo01...@postech.ac.kr<mailto:kdo01...@postech.ac.kr>,
kdo01...@gmail.com<mailto:kdo01...@gmail.com>

Tel: +82-054-279-1613, Mobile : +82-010-7350-2858

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