[Wien] phonon calculation

[Laurence Marks]

You should include -ec 0.0001 (or similar) and perhaps -cc 0.0005 in
the minimization, but I would be surprised it this is what happened.
Do a "grep -e :DIS *mini " to see if it did not properly converge. I
also suggest a "grep -e WARN *tM" and/or "grep -e :MIN *tM" to look at
the output of the minimization to see if it really worked -- it might
not have. (Read case.outputM)

With your new calculation did you re-initialize? If so, check if you
have the same symmetry operations in the new and old files, they might
have changed. You can use "x patchsymm ; cp *.struct_new *.struct "
(change as appropriate) in case of symmetry deviations which can occur
with older versions (but you seem to be using the current one).

N.B., the "-i 4000" should not be needed, at most "-i 100". If it
really needs so many iterations to converge something is wrong.
N.N.B., I assume that you used PORT in the minimization. If not, you
have to look much more carefully at the output to see if it worked.

2011/9/27 Yundi Quan <quan at ms.physics.ucdavis.edu>:
> Hi, I checked my calculations. And I can confirm that RMT, RKMAX does not
> change. The density seems to have converged at least according to the
> convergence criterion.
> :ENERGY convergence:  1 0.000001 .0000004300000000
> :CHARGE convergence:  1 0.0001 -.0000820
> :FORCE convergence: 1 0.1 .051 XCO .010 XCO .004 XC
> I also checked the structure file atom by atom and did not find any
> discrepancy.
>
> The only thing which I am not quite sure is the command I use
> min -i 1000 -s 4 -j 'runsp_lapw -I -i 4000 -fc 1.0 -p -it '
> I did not specify energy convergence criteria in my min calculation. I think
> that is the reason for the huge total force on atoms.
>
>
> Yundi
>
>
> 2011/9/27 Laurence Marks <L-marks at northwestern.edu>
>>
>> Some guesses:
>> # You changed RMT, RKMAX and the earlier ones were not good enough.
>> # You are not looking at a converged density.
>> # You made a mistake when copying the struct files.
>>
>> 99.99% probability that this is a "user error", I.e. you did something
>> wrong.
>>
>> On Sep 27, 2011 7:54 AM, "Yundi Quan" <quan at ms.physics.ucdavis.edu> wrote:
>> > Hi, Thanks for your suggestion. However, it turns out that I did use -fc
>> > 0.1. But still the force is very large. I paste the end of scf file
>> > below.
>> >
>> >
>> > FGL001: 1.ATOM -5.623000000 0.000000000 -0.010500000
>> > total forces
>> > :FGL002: 2.ATOM 0.000000000 0.000000000
>> > 0.000000000 total forces
>> > :FGL003: 3.ATOM -2.129500000 0.000000000
>> > 5.691000000 total forces
>> > :FGL004: 4.ATOM 33.965000000 5.442500000
>> > 24.743000000 total forces
>> > :FSUM : Sum of forces Fx,Fy,Fz 0.00000
>> > 0.00000 0.00000
>> >
>> >
>> > Yundi
>> >
>> > On Tue, Sep 27, 2011 at 12:08 AM, Stefaan Cottenier <
>> > Stefaan.Cottenier at ugent.be> wrote:
>> >
>> >>
>> >> I have another problem. After running 'min ....', I got a structure
>> >> with
>> >>> very small force. However, when I do another calculation with the
>> >>> structure I got, the total force on each atom becomes very large. What
>> >>> is the reason for this?
>> >>>
>> >>
>> >> Check whether it mentions partial forces or total forces at the end of
>> >> the
>> >> :FOR or :FGL lines. Probably your calculation with large forces was
>> >> done
>> >> withouth -fc, and lists only the partial forces. Add another iteration
>> >> with
>> >> TOT changed to FOR in case.in2(c) (which is what -fc does in its last
>> >> iteration).
>> >>
>> >> Stefaan
>> >>
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>> >>
>>
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>
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-- 
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
Research is to see what everybody else has seen, and to think what
nobody else has thought
Albert Szent-Gyorgi