[Pw_forum] primitive orthorohmbic face centred phonons

[Paolo Giannozzi]

On Wednesday 21 June 2006 18:15, Adeagbo Waheed Adeniyi wrote:

> I am trying to do phonon calculation of a primitive orthorohmbic face
> centred unit cell  with  2*2*2 uniform q grid, the nscf and the phonon
> calculation are right but when I performed q2r.x after the runs the program 
> stopped with error messages 

>       from init : error #         1
>       missing q-point(s)!

> [...] q-values obtained from c/a and b/a ratios using kpoints.x  are
>
>        0.0000000  0.0000000  0.0000000    for system.dynG
>        0.5000000 -0.5216606  0.4487578    for Q1
>        1.0000000  0.0000000  0.0000000    for Q2
>        0.0000000  0.0000000  0.8975155    for Q3
>        0.0000000  1.0433213  0.0000000    for Q4
>
> I used these values in phonon calculations.

there might be a mismatch between these points and what the code expects.
Even a small difference might do the job. Please try to calculate the phonon
dispersion with ldisp.true. and nq1=nq2=nq3=2

Paolo
-- 
Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
Scuola Normale Superiore    Phone:   +39/050-509876, Fax:-563513 
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