[Pw_forum] What is the unit of q point in ph.x output file?

[xirainbow]

Dear Lorenzo Paulatto:

On Mon, May 17, 2010 at 8:26 AM, Lorenzo Paulatto <paulatto at sissa.it> wrote:

> On Sat, 15 May 2010 16:21:47 +0200, xirainbow <nkxirainbow at gmail.com>
>
> > *      Dynamical matrices for ( 4, 4, 4,) uniform grid of q-points*
> > *      with only ( 4, 2, 2,) point requested*
> > *      (   1q-points):*
> > *      N       xq(1)       xq(2)       xq(3) *
> > *      1     0.50000     0.50000     0.50000 "*
> > *      Calculation of q =   0.5000  0.5000  0.5000*
> > *Question three:* Why                    *q=   0.5  0.5  0.5?*
> >                       I think it should be *q= -0.5  0.5  0.8713185.*
>
> I think you are right, well actually it would be 0.5 -0.5  0.8713185.
> But I've noticed that the subroutine computing the value of the q-point is
> actually called *after* the one the prints it; I guess the calculation is
> probably done at the correct point, it is the output on screen that is
> wrong. At the end of the calculation you can check inside the dynamical
> matrix file (matdyn) to be sure.
>
>

*Firstly，thank you for your patient reply：）** *

Secondly, in my output file, the frequency, degeneracy and symmetry of the
phonon
*                    Dynamical matrices for ( 4, 4, 4,) uniform grid of
q-points**
*                    with only ( 4, 2, 2,) point requested**
*                    (   1q-points):**
*                    N       xq(1)       xq(2)       xq(3) **
*                    1     0.50000     0.50000     0.50000 "**
are absolutely different from
"
*                      .......*
*                     ldisp = .false.,*
*                      .......*
*                      /*
*                     0.5000000 -0.5000000 0.8713186 *
"

Unfortunately, I have deleted these output files.
If you need, I will recalculate them and send it to you.


-- 
____________________________________
Hui Wang
School of physics, Nankai University, Tianjin, China
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