[Pw_forum] Plotting phonon dispersion

[elchatz at auth.gr]

Thank you. That makes sense.

Eleni


Quoting Vahid Askarpour <vh261281 at dal.ca>:

> a) If you skip amass, I think the codes use the mass in the previous runs.
>
> b) Did you use ibrav=0 in the scf run? The high-symmetry points you  
> defined are for ibrav=2. Otherwise, just specify the coordinates  
> explicitly.
>
> Cheers,
>
> Vahid
>
>> On Feb 19, 2018, at 9:29 AM, elchatz at auth.gr wrote:
>>
>>
>> Thank you Vahid Askarpour.
>>
>> I have two questions:
>>
>> a) Is there a problem if I don't specify amass?
>>
>> b) I have already done this procedure using the following files:
>>
>> ph.x:
>>
>> &inputph
>>   prefix   = 'Si',
>>   epsil    = .false.,
>>   fildyn   = 'diam.dyn',
>>   ldisp    = .true.
>>   fildvscf = 'dvscf'
>>   nq1=6,
>>   nq2=6,
>>   nq3=1,
>>   tr2_ph   =  1.0d-12,
>>   recover = .true.
>>  /
>>
>> This run ok
>>
>> q2r.in:
>>
>>  &input
>>   fildyn='diam.dyn',
>>   flfrc='Si.rc'
>>  /
>>
>> This run ok
>>
>> matdyn.in:
>>
>>  &input
>>     flfrc='Si.rc',
>>     flfrq='Si.freq',
>>     q_in_band_form=.true.
>>  /
>>  4
>>  gG 50
>>   X 50
>>   M 50
>>   gG 8
>>
>> And I got the following error:
>>
>>
>> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>>      Error in routine find_bz_type (1):
>>      Wrong ibrav
>>
>> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>>
>> Is it possible that this is because I messed up the names of the
>> files, or do I need to include explicitly the coordinates of the high
>> symmetry points?
>>
>>
>> Regards
>>
>> Eleni
>>
>>
>>
>>
>> Quoting Vahid Askarpour <vh261281 at dal.ca>:
>>
>>> Once you get all the .dyn files from the ph.x run, use the following
>>> input to q2r.x to get the force constants:
>>>
>>> &input
>>>   fildyn=’Si.dyn', zasr='simple', flfrc=’Si.ifc2’
>>> /
>>>
>>> Then use the following input to matdyn.x:
>>>
>>> &input
>>>    asr='simple',  amass(1)= 28.0855
>>>    flfrc=’Si.ifc2', flfrq=’Si.freq', q_in_band_form=.true.
>>> /
>>> 6  ! number of high-symmetry points
>>> 0.0 0.0 0.0 200
>>> 0.0 0.0 1.0 200
>>> etc.
>>>
>>> The coordinates of the high symmetry points should be in cartesian
>>> coordinates. 200 points will be calculated for each segment. The
>>> phonon dispersion is in the .gp output file.
>>>
>>> Cheers,
>>>
>>> Vahid
>>>
>>> Vahid Askarpour
>>> Department of Physics and Atmospheric Science
>>> Dalhousie University,
>>> Halifax, NS, Canada
>>>
>>>> On Feb 19, 2018, at 4:54 AM, elchatz at auth.gr wrote:
>>>>
>>>> Hello all,
>>>>
>>>> I am using ph.x to get the phonon frequencies and dynamical matrices
>>>> for an epw.x calculation, however, I would like to plot my phonon
>>>> dispersions from the ph.x calculation for far, as for example is shown
>>>> in
>>>>
>>>> http://epw.org.uk/Documentation/B-dopedDiamond
>>>>
>>>> I am lost as to how I can do that. My ph.x file is as follows,
>>>>
>>>> &inputph
>>>>  prefix   = 'Si',
>>>>  epsil    = .false.,
>>>>  fildyn   = 'diam.dyn',
>>>>  ldisp    = .true.
>>>>  fildvscf = 'dvscf'
>>>>  nq1=6,
>>>>  nq2=6,
>>>>  nq3=1,
>>>>  tr2_ph   =  1.0d-12,
>>>>  recover = .true.
>>>> /
>>>>
>>>> Do I need to use q2r.x and matdyn.x to the files for plotting?
>>>>
>>>>
>>>> Thank you
>>>>
>>>>
>>>>
>>>> --
>>>> Dr. Eleni Chatzikyriakou
>>>> Computational Physics lab
>>>> Aristotle University of Thessaloniki
>>>> elchatz at auth.gr - tel:+30 2310 998109
>>>>
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>>>
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>>
>>
>>
>> --
>> Dr. Eleni Chatzikyriakou
>> Computational Physics lab
>> Aristotle University of Thessaloniki
>> elchatz at auth.gr - tel:+30 2310 998109
>>
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-- 
Dr. Eleni Chatzikyriakou
Computational Physics lab
Aristotle University of Thessaloniki
elchatz at auth.gr - tel:+30 2310 998109