[Wien] Question about mini_lapw

[Laurence Marks]

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
>



-- 
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