Re: [Pw_forum] problem plotting graphene band structure

[Shan]

Dear Prof. Chibisov,

Thank you very much for your reply.

I am pleased to have your reply. I know you for the last 2 years, as I work
under Dr. Anurag Srivastava. Sure, I will convey your greetings to him.

Thank you again for your reply.

B. S. Bhushan


On Tue, Nov 29, 2016 at 7:49 PM, Andrey Chibisov 
wrote:

> Dear B.S. Bhushan,
> I see you're from Gwalior. I know this institution.
> Unless, of course I was not mistaken. Give please greetings to Dr. Anurag
> Srivastava.
> And now, with regard to the graphene.
> 1. The structure must be relaxing.
> 2. Add the nbnd parameter (with empty state), to watch the band gap.
> 3. In the graphene there is a spin-orbit interaction. Use the options:
> noncolin, lspinorb, starting_magnetization and Fully-Relativistic Pseudo
> to get a good value bandgap.
>
> So, I hope it will help.
>
> 29.11.2016, 22:03, "Shan" :
> > Dear Experts,
> >
> > I am beginner of QE. As part of the practice, I am extracting the basic
> structural and electronic properties of simple semiconducting materials, 1D
> and 2D structures. Things were fine untill i tried graphene. However, I
> stuck with graphene band structure for the last 3 days. As a beginner, I
> have done everything i can to resolve the problem. when i try to plot the
> band structure of 2 atom graphene, either i get a wrong band gap or an
> empty plot.
> >
> > Here I am attaching the SCF code and Bandstructure code. Can someone
> please verify and tell me where the problem is.
> >
> > SCF code:-
> >
> > 
> >   calculation='scf',
> >   outdir='.',
> >   prefix='pwscf',
> >   pseudo_dir='.',
> >   verbosity='low',
> >   tprnfor=.true.,
> >   tstress=.true.,
> > /
> >
> > 
> >   ibrav=4,
> >   celldm(1)=4.6509939378d0, celldm(3)=4.53,
> >   nat=2,
> >   ntyp=1,
> >   ecutwfc=30,
> >   ecutrho=120,
> >   input_dft='pbe',
> >   occupations='smearing',
> >   smearing='mv',
> >   degauss=0.005d0,
> > /
> >
> > 
> >   conv_thr=1d-08,
> >   mixing_beta=0.7d0,
> > /
> >
> > ATOMIC_SPECIES
> >   C 12.010700d0 C.pbe-n-rrkjus_psl.0.1.UPF
> >
> > ATOMIC_POSITIONS {crystal}
> >C   0.00d0   0.00d0   0.00d0
> >C   0.33d0   0.67d0   0.00d0
> >
> > K_POINTS {automatic}
> >   22 22 1 0 0 0
> >
> > Band Structure code:-
> >
> > 
> >   calculation='bands',
> >   outdir='.',
> >   prefix='pwscf',
> >   pseudo_dir='.',
> >   verbosity='high',
> > /
> >
> > 
> >   ibrav=4,
> >   celldm(1)=4.6509939378d0, celldm(3)=4.53,
> >   nat=2,
> >   ntyp=1,
> >   ecutwfc=30,
> >   ecutrho=120,
> >   input_dft='pbe',
> >   occupations='smearing',
> >   smearing='mv',
> >   degauss=0.005d0,
> > /
> >
> > 
> >   conv_thr=1d-08,
> >   mixing_beta=0.7d0,
> > /
> >
> > ATOMIC_SPECIES
> >   C 12.010700d0 C.pbe-n-rrkjus_psl.0.1.UPF
> >
> > ATOMIC_POSITIONS {crystal}
> >C   0.00d0   0.00d0   0.00d0
> >C   0.33d0   0.67d0   0.00d0
> >
> > K_POINTS {crystal_b}
> > 5
> >   0.000 0.0 0.1667 10 ! A
> >   0.000 0.000 0.0 20 ! G
> >   0. 0.57735027 0.0 20 ! K
> >   0. 0.0 0.0 20 ! M
> >   0.0 0.0 0.0 0 ! G
> >
> > Thank you very much in advance,
> >
> > Regards,
> > B S Bhushan
> > Ph.D Scholar
> > Indian Institute of Information Technology and Management, Gwalior,
> > India.
> >
> > ,
> >
> > ___
> > Pw_forum mailing list
> > Pw_forum@pwscf.org
> > http://pwscf.org/mailman/listinfo/pw_forum
>
>
> --
> 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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>
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Re: [Pw_forum] problem plotting graphene band structure

[Andrey Chibisov]

Dear B.S. Bhushan,
I see you're from Gwalior. I know this institution. 
Unless, of course I was not mistaken. Give please greetings to Dr. Anurag 
Srivastava.
And now, with regard to the graphene.
1. The structure must be relaxing.
2. Add the nbnd parameter (with empty state), to watch the band gap.
3. In the graphene there is a spin-orbit interaction. Use the options:
noncolin, lspinorb, starting_magnetization and Fully-Relativistic Pseudo to get 
a good value bandgap.

So, I hope it will help.

29.11.2016, 22:03, "Shan" :
> Dear Experts,
>
> I am beginner of QE. As part of the practice, I am extracting the basic 
> structural and electronic properties of simple semiconducting materials, 1D 
> and 2D structures. Things were fine untill i tried graphene. However, I stuck 
> with graphene band structure for the last 3 days. As a beginner, I have done 
> everything i can to resolve the problem. when i try to plot the band 
> structure of 2 atom graphene, either i get a wrong band gap or an empty plot.
>
> Here I am attaching the SCF code and Bandstructure code. Can someone please 
> verify and tell me where the problem is.
>
> SCF code:-
>
> 
>   calculation='scf',
>   outdir='.',
>   prefix='pwscf',
>   pseudo_dir='.',
>   verbosity='low',
>   tprnfor=.true.,
>   tstress=.true.,
> /
>
> 
>   ibrav=4,
>   celldm(1)=4.6509939378d0, celldm(3)=4.53,
>   nat=2,
>   ntyp=1,
>   ecutwfc=30,
>   ecutrho=120,
>   input_dft='pbe',
>   occupations='smearing',
>   smearing='mv',
>   degauss=0.005d0,
> /
>
> 
>   conv_thr=1d-08,
>   mixing_beta=0.7d0,
> /
>
> ATOMIC_SPECIES
>   C 12.010700d0 C.pbe-n-rrkjus_psl.0.1.UPF
>
> ATOMIC_POSITIONS {crystal}
>    C   0.00d0   0.00d0   0.00d0
>    C   0.33d0   0.67d0   0.00d0
>
> K_POINTS {automatic}
>   22 22 1 0 0 0
>
> Band Structure code:-
>
> 
>   calculation='bands',
>   outdir='.',
>   prefix='pwscf',
>   pseudo_dir='.',
>   verbosity='high',
> /
>
> 
>   ibrav=4,
>   celldm(1)=4.6509939378d0, celldm(3)=4.53,
>   nat=2,
>   ntyp=1,
>   ecutwfc=30,
>   ecutrho=120,
>   input_dft='pbe',
>   occupations='smearing',
>   smearing='mv',
>   degauss=0.005d0,
> /
>
> 
>   conv_thr=1d-08,
>   mixing_beta=0.7d0,
> /
>
> ATOMIC_SPECIES
>   C 12.010700d0 C.pbe-n-rrkjus_psl.0.1.UPF
>
> ATOMIC_POSITIONS {crystal}
>    C   0.00d0   0.00d0   0.00d0
>    C   0.33d0   0.67d0   0.00d0
>
> K_POINTS {crystal_b}
> 5
>   0.000 0.0 0.1667 10 ! A
>   0.000 0.000 0.0 20 ! G
>   0. 0.57735027 0.0 20 ! K
>   0. 0.0 0.0 20 ! M
>   0.0 0.0 0.0 0 ! G
>
> Thank you very much in advance,
>
> Regards,
> B S Bhushan
> Ph.D Scholar
> Indian Institute of Information Technology and Management, Gwalior,
> India.
>
> ,
>
> ___
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> http://pwscf.org/mailman/listinfo/pw_forum


-- 
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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Re: [Pw_forum] problem plotting graphene band structure

[Giovanni Cantele]

I do not have the time to check the coordinates now, but I guess that the 
coordinates of the k points are wrong. 
If I well remember, for example, the coordinates of the M point are 1/2 (and 
not 1/3) a reciprocal lattice vector,
so your M point, because you choose crystal coordinates, should look like 0.5 0 
0. Maybe other issues are present
for the other k points.

As a minor remark, if you are studying graphene (and not graphite), the 
coordinate of the A point is not needed
(band structure along a direction where you do not have a true periodicity).

Giovanni


> On 29 Nov 2016, at 13:02, Shan  wrote:
> 
> Dear Experts,
> 
> I am beginner of QE. As part of the practice, I am extracting the basic 
> structural and electronic properties of simple semiconducting materials, 1D 
> and 2D structures. Things were fine untill i tried graphene. However, I stuck 
> with graphene band structure for the last 3 days. As a beginner, I have done 
> everything i can to resolve the problem. when i try to plot the band 
> structure of 2 atom graphene, either i get a wrong band gap or an empty plot.
> 
> Here I am attaching the SCF code and Bandstructure code. Can someone please 
> verify and tell me where the problem is. 
> 
> SCF code:-
> 
> 
>   calculation='scf',
>   outdir='.',
>   prefix='pwscf',
>   pseudo_dir='.',
>   verbosity='low',
>   tprnfor=.true.,
>   tstress=.true.,
> /
> 
> 
>   ibrav=4,
>   celldm(1)=4.6509939378d0, celldm(3)=4.53,
>   nat=2,
>   ntyp=1,
>   ecutwfc=30,
>   ecutrho=120,
>   input_dft='pbe',
>   occupations='smearing',
>   smearing='mv',
>   degauss=0.005d0,
> /
> 
> 
>   conv_thr=1d-08,
>   mixing_beta=0.7d0,
> /
> 
> ATOMIC_SPECIES
>   C 12.010700d0 C.pbe-n-rrkjus_psl.0.1.UPF
> 
> ATOMIC_POSITIONS {crystal}
>C   0.00d0   0.00d0   0.00d0
>C   0.33d0   0.67d0   0.00d0
> 
> K_POINTS {automatic}
>   22 22 1 0 0 0
> 
> 
> Band Structure code:-
> 
> 
>   calculation='bands',
>   outdir='.',
>   prefix='pwscf',
>   pseudo_dir='.',
>   verbosity='high',
> /
> 
> 
>   ibrav=4,
>   celldm(1)=4.6509939378d0, celldm(3)=4.53,
>   nat=2,
>   ntyp=1,
>   ecutwfc=30,
>   ecutrho=120,
>   input_dft='pbe',
>   occupations='smearing',
>   smearing='mv',
>   degauss=0.005d0,
> /
> 
> 
>   conv_thr=1d-08,
>   mixing_beta=0.7d0,
> /
> 
> ATOMIC_SPECIES
>   C 12.010700d0 C.pbe-n-rrkjus_psl.0.1.UPF
> 
> ATOMIC_POSITIONS {crystal}
>C   0.00d0   0.00d0   0.00d0
>C   0.33d0   0.67d0   0.00d0
> 
> K_POINTS {crystal_b}
> 5
>   0.000 0.0 0.1667 10 ! A
>   0.000 0.000 0.0 20 ! G
>   0. 0.57735027 0.0 20 ! K
>   0. 0.0 0.0 20 ! M
>   0.0 0.0 0.0 0 ! G
> 
> 
> 
> Thank you very much in advance,
> 
> Regards,
> B S Bhushan
> Ph.D Scholar
> Indian Institute of Information Technology and Management, Gwalior, 
> India.
> 
> ___
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-- 

Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cant...@spin.cnr.it
Phone: +39 081 676910
Skype contact: giocan74

ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: http://people.na.infn.it/~cantele

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Re: [Pw_forum] Cannot allocate FFT (Trouble-shooting)

[GAO Zhe]

Dear QE users and developers,

The problem has been solved, so I just reply my own mail.
In QE version 5.4.0, it was found the error information from 
PW/src/allocate_fft.f90, but the real issue was raised from the subroutine 
sticks_maps defined in FFTXLib/stick_base.f90.
Just before the end of sticks_maps subroutine, the function MPI_ALLREDUCE is 
used. However, the first parameter MPI_IN_PLACE could not work with certain 
cases of MPICH2. Thus, the members of three integer arrays, st, stw and sts, 
become all zero.
So far, I just added three internal "shadows" integer arrays, _st_, _stw_ and 
_sts_. They copied all the members of st, stw and sts before calling 
MPI_ALLREDUCE. Thereafter, MPI_IN_PLACE are replaced by the "shadows".
After recompiling the code under MinGW with GNU compiler, the source code 
package of QE 5.4.0 was compiled to Windows 32-bit parallel executable files. 
Several computations has been done under Windows, it proved that the modified 
code is able to provide similar speed and the same results as running under 
Unix/Linux.
Please do not hesitate to let me know if one wants to test the Windows - 
parallel version QE 5.4.0.
Best Regards,


--
GAO Zhe, Dr.,
Research Engineer,
Gypsum Activity R - Asia,
Saint-Gobain Research Shanghai Co., Ltd.,

No. 55, Wenjing-road, Minhang-district, Shanghai, China,
Tel: +86-21-5475-7251





At 2016-10-16 11:01:46, "GAO Zhe"  wrote:

Dear QE users and developers,


I am trying to compile QE 5.4.0 under MinGW-32 with MPICH2.
However, pw.x met error while allocating FFT as following:
 G-vector sticks info
 
 sticks:   dense  smooth PW G-vecs:dense   smooth  PW
 Sum   0   0  000   0
 %%
 Error in routine allocate_fft (1):
 wrong ngm
 %%
 
During compiling, the only warning information was occurred for zhpev_drv.f90 
in LAXlib as:


gfortran -O3 -static  -x f95-cpp-input  -D__WIN32 -D__FFTW3 -D__GFORTRAN 
-D__STD_F95 -D__MPI -D__PARA   -I../include -I/$(MPICH_TOP)/include 
-I/local/include  -I../ELPA/src   -c zhpev_drv.f90
mpif.h:511.11:
Included at zhpev_drv.f90:14:
   SAVE /MPIFCMB1/, /MPIFCMB2/
   1
Warning: SAVE statement at (1) follows blanket SAVE statement
mpif.h:512.11:
Included at zhpev_drv.f90:14:
   SAVE /MPIFCMB3/, /MPIFCMB4/, /MPIFCMB5/, /MPIFCMB6/
   1
Warning: SAVE statement at (1) follows blanket SAVE statement
mpif.h:513.11:
Included at zhpev_drv.f90:14:
   SAVE /MPIFCMB7/, /MPIFCMB8/
   1
Warning: SAVE statement at (1) follows blanket SAVE statement


So far, I have no idea why the strange error took place. Would you like to 
share some comments with me how to avoiding the error?
Many thanks.
Best Regards,


--
GAO Zhe, Dr.,
Research Engineer,
Gypsum Activity R - Asia,
Saint-Gobain Research Shanghai Co., Ltd.,

No. 55, Wenjing-road, Minhang-district, Shanghai, China,
Tel: +86-21-5475-7251





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Re: [Pw_forum] B_field per Rydberg

[Paolo Giannozzi]

On Mon, Nov 28, 2016 at 8:42 PM, Mems Aghaee  wrote:

why magnetic field is per Rydberg?
>

because everything is in atomic (Rydberg) units and whoever wrote that
quantity was lazy, exactly as you are, since you ask:


> and how can i convert that to Tesla?
>

instead of doing the math

Paolo
-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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[Pw_forum] spin-orbit coupling

[Mortaza Aghtar]

Dear all,

I would like to raise my question since I didn't get any response.
Is there a way to calculate the spin-orbit coupling values for certain
spins?

Best regards,
Mortaza

-- 
Mortaza Aghtar, Ph.D.

Ulm Universität
Institut für Theoretiche Physik
Albert-Einstein-Allee 11
89081 Ulm

Office: 405/O25
Telephone: (+49) 731-50-22905
Group Page: http://qubit-ulm.com/
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[Pw_forum] problem plotting graphene band structure

[Shan]

Dear Experts,

I am beginner of QE. As part of the practice, I am extracting the basic
structural and electronic properties of simple semiconducting materials, 1D
and 2D structures. Things were fine untill i tried graphene. However, I
stuck with graphene band structure for the last 3 days. As a beginner, I
have done everything i can to resolve the problem. when i try to plot the
band structure of 2 atom graphene, either i get a wrong band gap or an
empty plot.

Here I am attaching the SCF code and Bandstructure code. Can someone please
verify and tell me where the problem is.

*SCF code:-*


  calculation='scf',
  outdir='.',
  prefix='pwscf',
  pseudo_dir='.',
  verbosity='low',
  tprnfor=.true.,
  tstress=.true.,
/


  ibrav=4,
  celldm(1)=4.6509939378d0, celldm(3)=4.53,
  nat=2,
  ntyp=1,
  ecutwfc=30,
  ecutrho=120,
  input_dft='pbe',
  occupations='smearing',
  smearing='mv',
  degauss=0.005d0,
/


  conv_thr=1d-08,
  mixing_beta=0.7d0,
/

ATOMIC_SPECIES
  C 12.010700d0 C.pbe-n-rrkjus_psl.0.1.UPF

ATOMIC_POSITIONS {crystal}
   C   0.00d0   0.00d0   0.00d0
   C   0.33d0   0.67d0   0.00d0

K_POINTS {automatic}
  22 22 1 0 0 0


*Band Structure code:-*


  calculation='bands',
  outdir='.',
  prefix='pwscf',
  pseudo_dir='.',
  verbosity='high',
/


  ibrav=4,
  celldm(1)=4.6509939378d0, celldm(3)=4.53,
  nat=2,
  ntyp=1,
  ecutwfc=30,
  ecutrho=120,
  input_dft='pbe',
  occupations='smearing',
  smearing='mv',
  degauss=0.005d0,
/


  conv_thr=1d-08,
  mixing_beta=0.7d0,
/

ATOMIC_SPECIES
  C 12.010700d0 C.pbe-n-rrkjus_psl.0.1.UPF

ATOMIC_POSITIONS {crystal}
   C   0.00d0   0.00d0   0.00d0
   C   0.33d0   0.67d0   0.00d0

K_POINTS {crystal_b}
5
  0.000 0.0 0.1667 10 ! A
  0.000 0.000 0.0 20 ! G
  0. 0.57735027 0.0 20 ! K
  0. 0.0 0.0 20 ! M
  0.0 0.0 0.0 0 ! G



Thank you very much in advance,

Regards,
B S Bhushan
Ph.D Scholar
Indian Institute of Information Technology and Management, Gwalior,
India.


scf.in
Description: Binary data


bs.in
Description: Binary data
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Re: [Pw_forum] Running in Parallel

[Paolo Giannozzi]

On Mon, Nov 28, 2016 at 7:49 PM, Mofrad, Amir Mehdi (MU-Student) <
am...@mail.missouri.edu> wrote:

However, after I compiled it to the newer version 6, apparently the
> simulation gets frozen (it dumps some information on the output file
> though). It recognizes the parallel version also (writes down the number of
> processors at the beginning of the output file). So I can't diagnose what
> the problem is.
>

you have to, because (I cannot be 100% sure, but 99.99%, yes) the problem
is on your machine's side, not on QE side. As a first step, look at
differences between the previous "make.sys" and the current "make.inc"

Paolo

-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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Re: [Pw_forum] spin-orbit interaction + pressure

[Lorenzo Paulatto]

On Monday, November 28, 2016 11:12:52 PM CET Maksim Markov wrote:
> Dear Maxim,
> 
> The results depend on pseudopotential you use. For example, you might have
> different exchange-correlation parts or include (or not include) semi-core
> states in valence. In this case it is not surprising that you have
> different
> results.

Just a little comment on top of what Maxime said. It is unrealistic to have 
very accurate phase diagrams with DFT, for several reason. But in particular, 
the energy scale is quite very wide: 300K correspond to just 0.0005Ry (0.5 
mRy)



-- 
Dr. Lorenzo Paulatto 
IdR @ IMPMC -- CNRS & Université Paris 6
phone: +33 (0)1 44275 084 / skype: paulatz
www:   http://www-int.impmc.upmc.fr/~paulatto/
mail:  23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05

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Re: [Pw_forum] kp

[Giovanni Cantele]

the correct statement is not that “there is no way” to calculate band structure 
for a molecule, but that 
a molecule has not a band structure. Band structure is a concept typical of 
solid state physics, and is related to
the occurrence, in crystals, of continuous energy intervals of allowed 
electronic levels separated by energy gaps
(where no electronic level can show up in an ideal crystal). The continuous 
distribution of levels in a band can be
described by assigning to each level a label, the k-vector, that represents the 
analogous of (but not the same as)
the momentum of the free electron when it moves in the free space instead of 
being subject to the periodic lattice
potential. The relation E(k) is just the energy dispersion and describes the 
band structure of the solid.

This is contrasted with discrete levels in molecules, where instead localised 
orbitals show up.

I want just to add that you can use plane waves to reproduce molecular 
orbitals, at the best level of approximation
allowed with the available exchange-correlation functionals. This means that if 
you calculate the molecular orbital of a molecule
within the GGA approximation, you get the same picture if you use plane wave 
packages, just as quantum-espresso, or other
packages based on localised basis sets. If using plane waves, you have just to 
take care of building appropriate super cells,
preventing the periodic replicas of the molecule form interacting with each 
other.

Giovanni

> On 29 Nov 2016, at 07:31, ashkan shekaari  wrote:
> 
> Dear Giovanni,
> Thank you so much for your explanatory response. So, as I understood, there 
> is no way to calculate band structure for a molecule and this is nonsensical. 
> Is it true?
> 
> 
> On Nov 29, 2016 1:46 AM, > 
> wrote:
> Just to add that plain wave is not a good approximation to reproduce 
> molecular orbitals.
> 
> Mortaza A
> 
> PhD of Physics 
> Ulm University, Germany 
> 
> On 28 Nov 2016, at 21:43, Giovanni Cantele  > wrote:
> 
>> if you try to ask the question: "what the k-point mesh is for?" you can 
>> easily understand
>> that a k-point mesh is for the Brillouin zone (BZ) sampling, that is, 
>> perform sums over k-points
>> that approximate, with a required level of accuracy, the integral over the 
>> whole BZ. This is
>> because in a crystal, the energy E(K) depends on the k vectors, and the same 
>> holds for the
>> wave functions. However, when you build for example a cubic supercell 
>> including vacuum to
>> simulate a molecule, you are actually dealing with a fictitious cubic 
>> crystal where the repeated
>> units are sufficiently far apart from each other to not interact.
>> 
>> Absence of interaction means flat (atomic-like) energy levels, that do not 
>> have dependence
>> on the k vector. That is, the E(K) dispersion that you get in the case of a 
>> molecule, provided
>> you include a sufficient vacuum space in your supercell, does not depend on 
>> k. If this is
>> the case, you can use only the gamma point (a larger grid means large but 
>> useless
>> computational time, because you are summing over eigenvalues at different 
>> k-points that 
>> are all the same!) for self consistency and BZ path is not needed, because 
>> if you select any
>> path you should get flat, k-independent bands
>> 
>> Giovanni
>> 
>> 
>>> On 28 Nov 2016, at 18:12, ashkan shekaari >> > wrote:
>>> 
>>> Dear experts,
>>> 
>>> Is it necessary using kpoint mesh when we are dealing with molecules?
>>> 
>>> In the case of a molecule in cubic vacuum, what path in BZ should be 
>>> selected?
>>> --
>>> Regards,
>>> Ashkan Shekaari
>>> Plasma Physics Research Center
>>> Science and Research Branch
>>> I A U, 14778-93855 Tehran, Iran.
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-- 

Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cant...@spin.cnr.it
Phone: +39 081 676910
Skype contact: giocan74

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