[Pw_forum] Relaxed Graphene Nanoribbon
Arles V. Gil Rebaza
arvifis at gmail.com
Tue May 10 03:03:05 CEST 2011
About the relationship between the reciprocal and real spaces, you can find
in some book of Solid State, authors like Ashcroft or Kittel. In order to
select the number of k-points you need to do convergence of the total energy
(or your observable) respect the number of k-points...!!! The same criteria
to select the optimal value of cut-off energy and perhaps also for the
length of the third vector (z direction) because you should consider the
periodicity of QE.
Best.
PhD std. Arles V. Gil Rebaza
Instituto de Física de La Plata
La Plata-Argentina
2011/5/9 swapnil chandratre <swapnil.chandratre at gmail.com>
> 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
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>>>>
>>>>
>>>
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>>
>>
>> --
>> ###---------> Arles V. <---------###
>>
>> _______________________________________________
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>>
>
>
> --
> 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
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>
>
--
###---------> Arles V. <---------###
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