[Pw_forum] help on q2r.x error!

[Eyvaz Isaev]

Hi,

--- mashangyi <shang.yi at hotmail.com> wrote:

> Dear all:  I encounter a problem when I use the
> q2r.x transform the dynamical matrix of gamma point
> to interatomic force constants in real space.  The
> system in my calculation is a Si-supercell composed
> of 64 Si atoms. I want to get some properties of it,
> like phdos, vibrational energy, entropy and so on.
> Following example02 and 06 indication, I calculate
> the dynamical matrix at the gamma point of the
> supercell after scf calculation( scf use 2x2x2
> k_points). When I call q2r.x to calculate IFC's in
> real space, it complains the follow
>
errors:+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>   transforming Si-bulk.q2r.in C(q) => C(R)...forrtl:
> severe (19): invalid reference to variable in
> NAMELIST input, unit 5, file stdin, line 5, position

There is very clean indication what is wrong: you
specified a parameter which does not exist in
NAMELIST.
 
> and q2r.x input-file:
> &input fildyn = 'si-bulk.dynG' zasr   = 'simple'
> flfrc  = 'si-bulk.fc' nr1=2, nr2=2, nr3=2 nfile  = 1

> filin  = 'si-bulk.dynG'/

There is no keyword "filin" in NAMELIST. That is your
problem, so, remove this line.

Besides, I did not understand you did scf-calculations
using 2x2x2 k-mesh, and then made phonon calculations.
If so, nr1=2 and etc. is not correct. 
Here you have to specify q-points mesh different of
k-points used in scf-calculations. Then q2r will be
able to do FFT F(q)=>F(R). So, you should put here 
nr1=1 etc. as you used only the Gamma point. Is the
use only the Gamma point is OK for FFT, some doubts.  

Probably, you have an enormous computational resource
and are very ambitious to calculate phonons for 64
atoms supercell. For ideal case these properties you
would like to calculate is just 32 times that these
for 2 atomic cell. 

Bests,
Eyvaz.

>  
>    I am still troubled with the errors though I
> searched some topics related it through the
> maillist. Would you help me solve it? Any
> suggestions are appreciated!
> Best regards!
> yours, shangyi
> ps: the q2r.x works well in example06
>  
>  
> Graduate school of China academy of science 
>
_________________________________________________________________
> ÖйúÊ®´óÈÈÃÅÂÃÓξ°µã
>
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-------------------------------------------------------------------
Prof. Eyvaz Isaev, 
Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, and 
Condensed Matter Theory Group, Uppsala University, Sweden Eyvaz.Isaev at fysik.uu.se, eyvaz_isaev at yahoo.com


       
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