[Wien] Question about mini_lapw

[Zsolt Rak]

Thank you Laurence for the explanation.
Just one more thing: suppose the attached inM file was generated by 
pairhess.  Should all atoms relax? (or just atoms 5 and 9 should relax).



 Marks wrote:

>Let me expand on my comment slightly. If you add constraints it should
>only be for a very, very specific reason (in my opinion), for instance
>you want to calculate the energy along a particular direction so you
>can estimate an activation energy barrier. In other cases it makes no
>sense, and in most cases will take LONGER to do a calculation when you
>decide which atoms should be relaxed, and which not. You also do not
>know what atoms should move, and your guess may well be wrong.
>
>I strongly recommend that you use the default case.inM produced by pairhess.
>
>N.B., it is 8.15 in the user guide.
>
>On Nov 8, 2007 2:13 PM, Laurence Marks <L-marks at northwestern.edu> wrote:
>  
>
>>See 8.15 which refers to how to do a constrained minimization.
>>
>>It should be noted that in general it is bad science to decide what
>>atoms should be relaxed and what should not be.
>>
>>
>>On Nov 8, 2007 11:01 AM, Zsolt Rak <rak at pa.msu.edu> wrote:
>>    
>>
>>>Dear all,
>>>
>>>I'm doing a defect calculations using the supercell method and I want to
>>>relax the positions of the atoms near the defect. My case.inM file is te
>>>following:
>>>
>>>PORT 2.0 0.35      # PORT/NEWT;  tolf, Initial Trust Radius
>>>0.0 0.0 0.0 1.0   #Atom  1 Generated by pairhess
>>>0.0 0.0 0.0 1.0   #Atom  2 Generated by pairhess
>>>0.0 0.0 0.0 1.0   #Atom  3 Generated by pairhess
>>>0.0 0.0 0.0 1.0   #Atom  4 Generated by pairhess
>>>1.0 1.0 1.0 1.0   #Atom  5 Generated by pairhess
>>>0.0 0.0 0.0 1.0   #Atom  6 Generated by pairhess
>>>0.0 0.0 0.0 1.0   #Atom  7 Generated by pairhess
>>>0.0 0.0 0.0 1.0   #Atom  8 Generated by pairhess
>>>1.0 1.0 1.0 1.0   #Atom  9 Generated by pairhess
>>>
>>> After running min -NI -j 'run -I -ex -fc 1',  I observed that all
>>>atoms were moved from their original positions, even though I only
>>>wanted to relax atoms 5 and 9.  How can I keep the positions fixed for
>>>some atoms, while relaxing others?
>>>
>>>Thank you,
>>>Zsolt
>>>_______________________________________________
>>>Wien mailing list
>>>Wien at zeus.theochem.tuwien.ac.at
>>>http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>>
>>>      
>>>
>>
>>--
>>Laurence Marks
>>Department of Materials Science and Engineering
>>MSE Rm 2036 Cook Hall
>>2220 N Campus Drive
>>Northwestern University
>>Evanston, IL 60208, USA
>>Tel: (847) 491-3996 Fax: (847) 491-7820
>>email: L-marks at northwestern dot edu
>>Web: www.numis.northwestern.edu
>>Commission on Electron Diffraction of IUCR
>>www.numis.northwestern.edu/IUCR_CED
>>
>>    
>>
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