[Pw_forum] primitive orthorohmbic face centred unit cell

[Adeagbo Waheed Adeniyi]

Does the solution apply to the problem I posted some 
weeks ago about primitive orthorohmbic face centred unit cell? See below 
the message.

I have been trying the suggestion of Paolo. When I started from a clean 
directories, I always have the final output such as system.dynG  being 
renamed to system.dynG1 etc. After the completing the runs, the new output 
system.dynG1 disappears and the phonon calculation restarts all over 
again instead of stopping after completing all the modes calculations.

For other q-values which I managed to obtain, I found out that ph.x does 
not give the correct output. I ended having gamma point output again 
instead of output  of new q-values supplied.

.i.e.

my input is for instance is 

phonons  at 0.5000000 -0.5216606  0.4487578
 &inputph
  tr2_ph=1.0d-12,
  prefix='system',
  trans= .true.,
 ldisp=.true.,
  nq1 =2,
  nq2=2,
  nq3=2,
  amass(1)= 69.723 ,
  amass(2)= 54.938049,
  amass(3)= 58.693,
  alpha_mix=0.2,
  outdir='tmp/',
  fildyn='Q1'
 /
0.5000000 -0.5216606  0.4487578

The output I got for this corresponds to as if I supplied  

q= 0.00000   0.000000 0.00000   which is wrong

Instead of have Q1 as my output, I had renamed Q12 as output.

=========output I got ============== 
phonons  at 0.5000000 -0.5216606  0.4487578
  3    4 10 10.9226214  0.9584775  1.1141869  0.0000000  0.0000000  
0.0000000
 1  'Ga  '  63543.2590482463274
 2  'Mn  '  50068.7388553597848
 3  'Ni  '  53490.8782370053159
    1    1      0.0000000      0.0000000      0.0000000
    2    2      0.5000000      0.5000000      0.5000000
    3    3      0.2500000      0.2500000      0.2500000
    4    3      0.7500000      0.7500000      0.7500000

     Dynamical  Matrix in cartesian axes

     q = (    0.000000000   0.000000000   0.000000000 )

  1  1
  0.17221145  0.00000000   -0.09288904  0.00000000    0.04686523   0.00000000
 -0.09288904  0.00000000    0.22113312  0.00000000   -0.03557558  0.00000000
  0.04686523  0.00000000   -0.03557558  0.00000000    0.10356385  0.00000000
  1  2
 -0.04635318  0.00000000    0.00062615  0.00000000   -0.00136149  0.00000000
  0.00146245  0.00000000   -0.06910707  0.00000000   -0.00490099  0.00000000

.............



In the previous calculations I did without suplying  nq1 =2, nq2=2, 
nq3=2, and  ldisp=.true., I got all my Q-values but yield an error  
when I ran q2r.x . 
====================================

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

This is why I restarted with the options  nq1 =2, nq2=2,
nq3=2, and  ldisp=.true., as Paolo suggested but the running  are 
mis-behaving.  


I don't know if the message below is applicable.
===============================================================
Dear Eyvaz, dear all,

some time ago I posted a problem with some phonon calculation. I had some
additional dynamical matrices in the files which yield an error of q2r.x
"q-point not allowed". Here just some notes how I solved it for me.

I circumvented this problem by removing the "not allowed" matrices and
everything worked well. My first attempt (as I wrote) failed due to the
fact that I removed by accidence also one "allowed" point, and this one
was missing then.

Thus, q2r.x is working properly as expected.

As I wrote, I circumvented the problem for me, I didn't solve it.
It seems to be, that the ph.x finds some equivalent q points which q2r.x
doesn't accept. They differ from the original one just by some "-".
If someone is interested in solving this problem (if it is really a
problem ...), then I would like to help if it is possible.

All the best,
Katalin

=====================================================



Message earlier posted.


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