[Pw_forum] Quantum Espresso
Ubaid Mohd
onlymubaid at gmail.com
Sat Jul 8 07:57:08 CEST 2017
I tried with the same but it showing the problem after some iteration and I
enclosed my input file please have a look at that ........
iteration # 3 ecut= 75.00 Ry beta=0.70
Davidson diagonalization with overlap
ethr = 5.28E-03, avg # of iterations = 2.0
negative rho (up, down): 3.835E-05 0.000E+00
total cpu time spent up to now is 4472.4 secs
total energy = -34.18814464 Ry
Harris-Foulkes estimate = -34.19240349 Ry
estimated scf accuracy < 0.00935740 Ry
iteration # 4 ecut= 75.00 Ry beta=0.70
Davidson diagonalization with overlap
c_bands: 1 eigenvalues not converged
c_bands: 1 eigenvalues not converged
c_bands: 1 eigenvalues not converged
c_bands: 1 eigenvalues not converged
*Mohammad Ubaid*
*PhD Research Scholar*
*Department of Physics*
*Jamia Millia Islamia University*
*New Delhi - 110025*
On Thu, Jul 6, 2017 at 11:53 PM, Biswajit Santra <bishalya at gmail.com> wrote:
> You can find many water crystal structure here http://aip.scitation.org/
> doi/suppl/10.1063/1.4824481
>
> However, you may not need it since you need isolated water molecule
> energy. A large cell of about 20-25 Angstrom length is typically sufficient
> to have negligible interactions with the periodic images.
>
> Best,
>
> Biswajit Santra
> Mobile: +1-609-227-9202
> http://www.princeton.edu/~bsantra/
>
> On Thu, Jul 6, 2017 at 12:07 PM, Ubaid Mohd <onlymubaid at gmail.com> wrote:
>
>> Should I relax the isolated water molecule inside the cubical box?
>>
>> On 6 Jul 2017 5:17 pm, "Nicola Marzari" <nicola.marzari at epfl.ch> wrote:
>>
>>> On 06/07/2017 13:39, Andrey Chibisov wrote:
>>> > Dear Mohammad,
>>> > You need to place the isolated water molecule in big cubic box (with
>>> the side about 15 Angstrom or bigger) and calculate the total energy. This
>>> will be the total energy of the isolated water molecule.
>>>
>>> Indeed! And you can monitor the length of the box to see when the total
>>> energy converges to the isolated limit (water has a dipole-dipole
>>> interaction with its periodic image).
>>>
>>> QE has also the option of using open boundary conditions, although I
>>> admit I'm not sure where they are implemented (certainly in environ,
>>> but maybe somewhere else).
>>>
>>> Last, if you use periodic boundary conditions, and want to be fussy,
>>> a bcc cell is considered the optimal traedoff - due to the fact that
>>> for a given volume it puts the periodic neighbors quite a bit farther
>>> (6-7%) than the cubic cell; not as much as the fcc cell, but compared
>>> to fcc you have only 8 rather than 12 neightbours.
>>>
>>> Probably noone in the history of simulations has tested this - so you
>>> could make a small paper out of it!
>>>
>>> nicola
>>>
>>>
>>> >
>>> > 06.07.2017, 15:30, "Ubaid Mohd" <onlymubaid at gmail.com>:
>>> >> Dear all,
>>> >> I am doing the calculations of water confinement between graphene
>>> sheets. I have done all the relaxation calculations. After relaxation I
>>> found the total energy of the graphene sheet, I also need to find the
>>> total energy of the water molecule to get the total binding energy of the
>>> system.
>>> >> My question is, to find the total energy of the water molecule what
>>> should be the crystal structure of water and how I create the unit cell of
>>> water.
>>> >> Thanks in advance.
>>> >>
>>> >> Mohammad Ubaid
>>> >> PhD Research Scholar
>>> >> Department of Physics
>>> >> Jamia Millia Islamia University
>>> >> New Delhi - 110025
>>> >>
>>> >> On Mon, Jun 19, 2017 at 3:51 PM, Ubaid Mohd <onlymubaid at gmail.com>
>>> wrote:
>>> >>> Thanks Sir
>>> >>>
>>> >>> Mohammad Ubaid
>>> >>> PhD Research Scholar
>>> >>> Department of Physics
>>> >>> Jamia Millia Islamia University
>>> >>> New Delhi - 110025
>>> >>>
>>> >>> Mohammad Ubaid
>>> >>> PhD Research Scholar
>>> >>> Department of Physics
>>> >>> Jamia Millia Islamia University
>>> >>> New Delhi - 110025
>>> >>>
>>> >>> On Mon, Jun 19, 2017 at 3:50 PM, Giovanni Cantele <
>>> giovanni.cantele at spin.cnr.it> wrote:
>>> >>>> Users of this forum are usually kindly requested to provide their
>>> name and affiliation, when posting messages!!!!!!!! ;-)
>>> >>>>
>>> >>>> The scf run reads the position in the input file, whichever run has
>>> come before. nscf read positions from outdir, if any
>>> >>>>
>>> >>>> Giovanni
>>> >>>>
>>> >>>>> On 19 Jun 2017, at 12:14, Ubaid Mohd <onlymubaid at gmail.com> wrote:
>>> >>>>>
>>> >>>>> Then only for scf run, following the relaxation run, whether we
>>> use initial coordinates or optimized coordinates
>>> >>>>>
>>> >>>>> On Mon, Jun 19, 2017 at 3:29 PM, Giovanni Cantele <
>>> giovanni.cantele at spin.cnr.it> wrote:
>>> >>>>>> Users of this forum are usually kindly requested to provide their
>>> name and affiliation, when posting messages! ;-)
>>> >>>>>>
>>> >>>>>> If, after a relaxation run, you execute an nscf (e.g. for band
>>> structure or DOS ) calculation, the code will automatically read optimised
>>> positions from outdir, even though the input file contains the initial
>>> coordinates. On the other hand, for an scf run, following a relaxation run,
>>> even though the outdir contains information about the relaxed coordinates,
>>> pw.x will always use the positions specified in the input file (you might
>>> want to calculate total energy and other properties at geometries other
>>> than the relaxed one).
>>> >>>>>>
>>> >>>>>> Giovanni
>>> >>>>>>
>>> >>>>>>> On 19 Jun 2017, at 09:58, Ubaid Mohd <onlymubaid at gmail.com>
>>> wrote:
>>> >>>>>>>
>>> >>>>>>> Dear all,
>>> >>>>>>> I have run some relaxed calculations. In case of scf /nscf/band
>>> calculations what coordinates should I be use, optimized coordinates from
>>> relaxed output file or by default it takes from prefix
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>>> >
>>> > --
>>> > Best regards,
>>> > Andrey Chibisov. Ph.D.
>>> > Numerical method of mathematical physics Laboratory,
>>> > Computational Center, Russian Academy of Sciences.
>>> > Khabarovsk, Russia
>>> > Web page: https://www.researchgate.net/profile/A_Chibisov
>>> > http://ru.linkedin.com/pub/andrey-chibisov/55/253/986/en
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>>>
>>>
>>> --
>>> ----------------------------------------------------------------------
>>> Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
>>> Director, National Centre for Competence in Research NCCR MARVEL, EPFL
>>> http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project
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