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Dear QE Developers and Users</div>
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I am currently working on a project in which I must study the properties of materials with point defects, among the calculations that I must perform is the calculation of the zpl, in some publications and in messages of this forum, I have read that it is possible
to make such a calculation with QE, but I have had some difficulties with the systems in which I am working, I explain below:
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The ZPL calculation, requires identifying the orbitals participating in the excitation process and setting the occupancy of those orbitals (occupancion = 'from_input', occupancies in card "OCCUPATIONS"). Then minimize energy and geometry using the DeltaSCF
method. But this calculation requires that the order of the orbitals is not altered, for example, the orbital 123 at the beginning of the minimization process (electronic and geometrical) should correspond with the orbital 123 at the end of the minimization
(the projection of the badan at the defect site should be the same at the beginning and end of the calculation) , however in the calculations that I perform this does not happen, the orbitals change order and the total energy has an oscillatory behavior, because
of this I can not optimize the geometry of the excited state. <br>
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I was reviewing the manual and I did not find any keywork that maintains the order of the orbitals during the whole minimization process. I would like to know if there is any way to modify the source code of the program so that it does not alter the order of
the orbitals?</div>
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Best regards</div>
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Dani Marin</div>
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PhD Student</div>
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National University of Colombia</div>
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