Geometry optimization keeping symmetry

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Geometry optimization keeping symmetry
Date: 2023/09/25 22:56 Name: H.Ueda Dear developers, I am trying to calculate using geometry optimization. In high symmetry crystal, however, geometry optimization makes symmetry reduction. Of cource, MD.Fixed.XYZ suppresses it in some extent. It is not enough for our purpose. Is there any methods to optimize geometry keeping space group symmetry of the crystal? Best regards, H. Ueda

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Re: Geometry optimization keeping symmetry ( No.1 )

Date: 2023/09/28 21:38
Name: H.Ueda

Dear all,

I have tried several procedures, and one of them seems to give a good result. So I want to show the procedure.

After variable cell optimization, geometry optimization with MD.maxIter=2 and averaging coordination considering symmetry are repeatedly conducted. Then maximum force gradually reduces keeping symmetry. Although it is still running, I think it will converge within a few days.

To average coordination, I used the string in cif file given blow.
1 'x+1/2, y, -z+1/2'
2 'x, -y+1/2, z'
3 '-x+1/2, y+1/2, z+1/2'
4 '-x, -y, -z'
5 '-x+1/2, -y, z+1/2'
6 '-x, y+1/2, -z'
7 'x+1/2, -y+1/2, -z+1/2'
8 'x, y, z'

I am happy, if this procedure is helpful for others facing similar problem.

Best regards,
H. Ueda

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