[Pw_forum] Relaxed Graphene Nanoribbon

swapnil chandratre swapnil.chandratre at gmail.com
Mon May 9 19:33:53 CEST 2011


Hello,


Thank you all for your responses, I was using a software to generate the
geometry of ribbon, it gave me the data regarding the *unit cell *dimensions
so I just transfered the data from there. And when I visualized it there, it
seemed to be perfect, I am trying to install XCrysden so that I can avoid
such issues again.

Arles, can you shed some knowledge on how to go for the k points, as it is
1d,I assume 100 k points may be sufficient to give reasonable idea, I just
randomly selected 25 as a starting point, and can anyone suggest any reading
material or approach towards defining the cut off energies and K points.

Thank you.

On Mon, May 9, 2011 at 9:44 AM, Arles V. Gil Rebaza <arvifis at gmail.com>wrote:

> Your unit cell vectors are wrong, because many atoms positions are out the
> unit cell..!! futhermore, why do you put 25 1 1 k-points...?? remember that
> the reciprocal space is inversely proportional to real space....!!!
>
> Best.
>
> PhD std. Arles V. Gil Rebaza
> Instituto de Física de La Plata
> La Plata-Argentina
>
>
> 2011/5/9 mousumi uk <larikamonu at gmail.com>
>
>> Your unit cell is wrong.... visualize your structure in xcrysden and
>> correct the CELL_PARAMETERS.
>>
>> Best regards,
>> Mousumi
>>
>> On Mon, May 9, 2011 at 6:36 AM, swapnil chandratre <
>> swapnil.chandratre at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> I have prepared an input file for a porous graphene nanoribbon, can
>>> anyone please comment if there are any errors with the file.
>>>
>>> &control
>>>     calculation  = 'relax'
>>>     restart_mode = 'from_scratch'
>>>     pseudo_dir    = '/home/s/schandratre/Espresso/pseudo'
>>>     outdir        = '/home/s/schandratre/Espresso/run'
>>>
>>>  /
>>>  &system
>>>
>>>     ibrav = 0
>>> nat=96
>>> ntyp=2
>>> ecutwfc=80.0
>>> ecutrho = 600.0
>>> occupations = 'smearing'
>>> degauss=0.02
>>> smearing = 'gaussian',
>>>  /
>>>  &electrons
>>>     conv_thr = 1.0d-6,
>>>     mixing_beta=0.3,
>>>   /
>>> &ions
>>> ion_dynamics='damp'
>>> pot_extrapolation='second_order'
>>> wfc_extrapolation='second_order'
>>> /
>>>
>>> ATOMIC_SPECIES
>>> C 12.0000 C.pz-rrkjus.UPF
>>> H 1.00000 H.pz-rrkjus.UPF
>>>
>>> ATOMIC_POSITIONS {angstrom}
>>>   C   2.841720  5.953494  5.000000
>>>   C   3.552150  7.183995  5.000000
>>>   C   1.420860  5.953494  5.000000
>>>   C   2.841720  8.414496  5.000000
>>>   C   3.552150  9.644997  5.000000
>>>   C   0.710430  7.183995  5.000000
>>>   C   1.420860  8.414496  5.000000
>>>   C   2.841720  10.87550  5.000000
>>>   C   3.552150  12.10600  5.000000
>>>   C   0.710430  9.644997  5.000000
>>>   C   1.420860  10.87550  5.000000
>>>   C   2.841720  13.33650  5.000000
>>>   C   3.552150  14.56700  5.000000
>>>   C   0.710430  12.10600  5.000000
>>>   C   1.420860  13.33650  5.000000
>>>   C   0.710430  14.56700  5.000000
>>>   H   3.392220  5.000000  5.000000
>>>   H   0.870360  5.000000  5.000000
>>>   H   3.001650  15.52049  5.000000
>>>   H   1.260930  15.52049  5.000000
>>>   C   7.104300  5.953494  5.000000
>>>   C   7.814730  7.183995  5.000000
>>>   C   5.683440  5.953494  5.000000
>>>   C   7.104300  8.414496  5.000000
>>>   C   4.973010  7.183995  5.000000
>>>   C   5.683440  8.414496  5.000000
>>>   C   7.104300  10.87550  5.000000
>>>   C   7.814730  12.10600  5.000000
>>>   C   4.973010  9.644997  5.000000
>>>   C   5.683440  10.87550  5.000000
>>>   C   7.104300  13.33650  5.000000
>>>   C   7.814730  14.56700  5.000000
>>>   C   4.973010  12.10600  5.000000
>>>   C   5.683440  13.33650  5.000000
>>>   C   4.973010  14.56700  5.000000
>>>   H   7.654800  5.000000  5.000000
>>>   H   5.132940  5.000000  5.000000
>>>   H   7.264230  15.52049  5.000000
>>>   H   5.523510  15.52049  5.000000
>>>   C   11.36688  5.953494  5.000000
>>>   C   12.07731  7.183995  5.000000
>>>   C   9.946020  5.953494  5.000000
>>>   C   11.36688  8.414496  5.000000
>>>   C   12.07731  9.644997  5.000000
>>>   C   9.235590  7.183995  5.000000
>>>   C   11.36688  10.87550  5.000000
>>>   C   12.07731  12.10600  5.000000
>>>   C   11.36688  13.33650  5.000000
>>>   C   12.07731  14.56700  5.000000
>>>   C   9.235590  12.10600  5.000000
>>>   C   9.946020  13.33650  5.000000
>>>   C   9.235590  14.56700  5.000000
>>>   H   11.91738  5.000000  5.000000
>>>   H   9.395520  5.000000  5.000000
>>>   H   11.52681  15.52049  5.000000
>>>   H   9.786090  15.52049  5.000000
>>>   C   15.62946  5.953494  5.000000
>>>   C   16.33989  7.183995  5.000000
>>>   C   14.20860  5.953494  5.000000
>>>   C   15.62946  8.414496  5.000000
>>>   C   16.33989  9.644997  5.000000
>>>   C   13.49817  7.183995  5.000000
>>>   C   14.20860  8.414496  5.000000
>>>   C   15.62946  10.87550  5.000000
>>>   C   16.33989  12.10600  5.000000
>>>   C   13.49817  9.644997  5.000000
>>>   C   14.20860  10.87550  5.000000
>>>   C   15.62946  13.33650  5.000000
>>>   C   16.33989  14.56700  5.000000
>>>   C   13.49817  12.10600  5.000000
>>>   C   14.20860  13.33650  5.000000
>>>   C   13.49817  14.56700  5.000000
>>>   H   16.17996  5.000000  5.000000
>>>   H   13.65810  5.000000  5.000000
>>>   H   15.78939  15.52049  5.000000
>>>   H   14.04867  15.52049  5.000000
>>>   C   19.89204  5.953494  5.000000
>>>   C   20.60247  7.183995  5.000000
>>>   C   18.47118  5.953494  5.000000
>>>   C   19.89204  8.414496  5.000000
>>>   C   20.60247  9.644997  5.000000
>>>   C   17.76075  7.183995  5.000000
>>>   C   18.47118  8.414496  5.000000
>>>   C   19.89204  10.87550  5.000000
>>>   C   20.60247  12.10600  5.000000
>>>   C   17.76075  9.644997  5.000000
>>>   C   18.47118  10.87550  5.000000
>>>   C   19.89204  13.33650  5.000000
>>>   C   20.60247  14.56700  5.000000
>>>   C   17.76075  12.10600  5.000000
>>>   C   18.47118  13.33650  5.000000
>>>   C   17.76075  14.56700  5.000000
>>>   H   20.44254  5.000000  5.000000
>>>   H   17.92068  5.000000  5.000000
>>>   H   20.05197  15.52049  5.000000
>>>   H   18.31125  15.52049  5.000000
>>>
>>> CELL_PARAMETERS
>>> 19.200000 0.000000 0.000000
>>> 0.0000000 21.90350 0.000000
>>> 0.0000000 0.000000 10.00000
>>>
>>> K_POINTS {automatic}
>>>  25 1 1  0 0 0
>>>
>>>
>>> --
>>> Regards,
>>> Swapnil Chandratre
>>> Graduate Student
>>> Dept. of Mechanical Engineering,
>>> University of Houston,
>>> Houston, TX
>>> (M)-713-294-9546
>>>
>>> _______________________________________________
>>> Pw_forum mailing list
>>> Pw_forum at pwscf.org
>>> http://www.democritos.it/mailman/listinfo/pw_forum
>>>
>>>
>>
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>
>
> --
> ###--------->   Arles V.   <---------###
>
> _______________________________________________
> Pw_forum mailing list
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>
>


-- 
Regards,
Swapnil Chandratre
Graduate Student
Dept. of Mechanical Engineering,
University of Houston,
Houston, TX
(M)-713-294-9546
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