[Pw_forum] normal modes visualization

[Giuseppe Mattioli]

Dear Emile (and all)
Only one further question.
I've run the CH4 example (pw.x, ph.x, and dynmat.x). the dynmat.x calculation 
produce a series of files. dynmat.axsf contains the previously mentioned 
forces on ions (there is also a dynmat.mold file which seems to contain 
normal modes, to be opened with molden; I will give a try...). The standard 
output of dynmat.x contains a list of CH3 normal modes:

#  mode   [cm-1]     [THz]       IR
    1      0.00    0.0000    0.0000
    2      0.00    0.0000    0.0000
    3      0.00    0.0000    0.0000
    4      0.00    0.0000    0.0000
    5      0.00    0.0000    0.0000
    6      0.00    0.0000    0.0000
    7   1262.12   37.8372    0.3460
    8   1263.53   37.8796    0.3438
    9   1265.00   37.9235    0.3451
   10   1482.79   44.4527    0.0000
   11   1483.78   44.4823    0.0000
   12   2947.63   88.3671    0.0000
   13   3069.30   92.0148    0.4037
   14   3070.51   92.0509    0.4045
   15   3071.15   92.0701    0.4038

I was wondering how the last column (IR) is related to the infrared dipole 
matrix or oscillator strenght. The Herzberg bible says indeed that "all four 
are Raman active but only the two triply degenerate vibrations are infrared 
active".

Thanks again

Giuseppe


On Thursday 20 October 2011 13:17:29 Emine Kucukbenli wrote:
> Ciao Giuseppe,
>
> Yes there is a small program that does that : dynmat.x
> Call it like this:
> $espresso_dir/bin/dynmat.x
>
> then feed this one line input (no need for a separate input file)
> &input fildyn='yourfile' /
>
> it produces dynmat.axsf where the normal modes are represented as
> forces in xcrysden,
> an animated xsf file, one frame per mode.
>
> xcrysden --axsf dynmat.axsf
>
> This is how it was working last time i checked, i dont think anything
> has changed..
> emine kucukbenli, phd student, sissa, italy
>
> ps: after writing i remembered this:
> http://people.sissa.it/~degironc/QE-Tutorial/tutorial_phon.htm
> check the "Phonons at Gamma point" section - last bit.
>
> Quoting giuseppe.mattioli at mlib.ism.cnr.it:
> > Dear all
> > Does anybody know if there is any post-processing tool which allows
> > one to visualize normal modes calculated with phonon.x or phcg.x in
> > real space, as, for instance, ion displacement movies to be opened
> > with xcrysden or xmakemol?
> > Thank you in advance
> >
> > Giuseppe
> >
> > Giuseppe Mattioli
> > ISM-CNR
> > Italy
> >
> >
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   Giuseppe Mattioli                            
   CNR - ISTITUTO DI STRUTTURA DELLA MATERIA   
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