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vkloff
koppolu mahendrakoppolu mahendra 22 Mar 2017 08:38
in discussion Forum / Controversy » vkloff

If any one of the experts of the TDDF explains about "vkloff", can be very helpful for beginners like me.

vkloff by koppolu mahendrakoppolu mahendra, 22 Mar 2017 08:38

dear all

I try to use Elastic and quantum-espresso to calculate graphene. I same problem.

the input file is:
&CONTROL
calculation = "relax",
prefix = "graphene",
pseudo_dir = " ./pseudo",
outdir = "./tmp",
tstress = .TRUE.
tprnfor = .TRUE.
/
&SYSTEM
ibrav = 8,
celldm(1) = 4.65107713,
celldm(2) = 1.732050806,
celldm(3) = 8.125971409,
nat = 4,
ntyp = 1,
ecutwfc = 32.D0,
ecutrho = 320.D0,
occupations ='fixed'
nosym =.TRUE.
/
&ELECTRONS
conv_thr = 1.D-7,
mixing_beta = 0.7D0,
mixing_mode = 'TF',
/
&IONS
ion_dynamics = 'bfgs',
/
ATOMIC_SPECIES
C 12.0107 C.pbe-van_ak.UPF
ATOMIC_POSITIONS {crystal_sg}
C 0.75000000 0.833333333 0.000000000
C 0.25000000 0.666666667 0.000000000
C 0.25000000 0.333333333 0.000000000
C 0.75000000 0.166666667 0.000000000
K_POINTS {automatic}
5 3 1 0 0 0

run Elastic_Setup_ESPRESSO then get that :

Number and name of space group: 191 (P 6/m m m)
Hexagonal I structure in the Laue classification.
This structure has 5 independent second-order elastic constants.

…. Oops ERROR: ibrav = 8, It means "Orthorhombic" structure.
But this structure can be represented by "Hexagonal" system.
THEY ARE NOT COMPATIBLE. Please Look at sgroup.out

I'm surprising this job sometimes run without error but this time isn't run.

Thanks so much
Elham

vorwerkcvorwerkc 23 Feb 2017 14:59
in discussion Forum / Support Questions » DOS

Hi Julia,
I recommend using the excalibr module (https://github.com/vorwerkc/excalibr) for the analysis of the DOS.
Using the module, you can obtain the total DOS for Nitrogen as:

from excalibr import parsedos
 
dos=parsedos.dos('dos.xml')
for i in range(len(dos.energies)):
    print(len(dos.energies, dos.speciesl(1,1)))

This snippet prints the projected DOS of the species 1 and l=1 for each energy point. The numbering of the species is the same as in the input file.

If you have any other questions, feel free to contact me per email.

Best regards,
Christian Vorwerk
(exciting team)

by vorwerkcvorwerkc, 23 Feb 2017 14:59
Julia (guest) 23 Feb 2017 12:05
in discussion Forum / Support Questions » DOS

Dear Caterina,

Thank you for your answer.

In fact, I have another questions concerning DOS. I simulated the (P)DOS of TiN. I already plotted it with xmgrace - every thing worked fine by following your tutorial. Now I want to plot the total DOS BUT only for Nitrogen. I want to sum up all orbital quantum numbers and each atom of species.

I already figured out a very time-consuming method, by exporting the data from xmgrace for each atom and each quantum number individually but I really hope there is another (easier) way.

Thank you for your help so far.

kind regards,
Julia

by Julia (guest), 23 Feb 2017 12:05
Re: DOS
Caterina CocchiCaterina Cocchi 22 Feb 2017 20:34
in discussion Forum / Support Questions » DOS

Dear Julia,

the PDOS in exciting is currently not resolved in real spherical harmonics. So at the moment it is not possible to convert your results into actual px, py, and pz components. We plan to make this feature available in the next release of the code.

Best regards,
Caterina Cocchi
(exciting team)

Re: DOS by Caterina CocchiCaterina Cocchi, 22 Feb 2017 20:34
DOS
Julia (guest) 20 Feb 2017 08:39
in discussion Forum / Support Questions » DOS

Dear exciting Team,

I have successfully calculate the DOS for my material. Exciting computes the DOS with respect to the l-m-basis / or projecting it on the l-m-basis. Unfortunately to proceed with my work I need to convert these results into the px, py, pz "representation". Do you have any advise for me to do so?

I am really looking forward to your answer.

kind regards,
Julia

DOS by Julia (guest), 20 Feb 2017 08:39

Dear Santiago

Thanks a lot.
So, I use the benefits of "scissor" in my case. Actually, it isn't so urgent.

Regards

M. Tarighi
Malek-Ashtar university, Iran

Dear Julia,

the input keyword you chose is to be considered obsolete, as it is not yet supported. In order to calculate ELNES spectra properly, we suggest you to use the Bethe-Salpeter formalism, as described in the corresponding tutorial: http://exciting-code.org/carbon-x-ray-absorption-spectra-using-bse. In this way, you have the full freedom to select which atom to excite.

We hope this solves your problem. Do not hesitate to contact us for any further question.

Best regards,
Caterina Cocchi
(exciting team)

Dear exciting group,

I am trying to do an ELNES calculation for rutile. I already went through the input reference exciting but I cannot figure out how to properly use it. How do I tell exciting to do the ELNES calculation only for (in my case) the oxygen. I tried this code

<properties>
<elnes wmax="2.0"/>
</properties>

but all I get in the ELNES.OUT file are zeros. Are there any requisites before starting the ELNES calculation?

I hope you can help me solve this problem.

kind regards,
Julia

ELNES calculation for rutile by Julia (guest), 13 Feb 2017 10:30

Dear M. Tarighi. This feature is not yet contained in the current release of exciting, nevertheless it is planned for the next release. Please contact me directly per email in case you need it urgently.

In the current release, you can still mimic quasi-particle eigenvalues in TDDFT by applying a shift to the conduction KS eigenvalues, in order to correct the KS gap. This you can do by setting the "scissor" attribute in the "xs" element.

Regards,
Santiago Rigamonti.
(exciting team)

Dear exciting group!

I'd like to perform a tddft calculation using quasi-particle corrected eigenvalues obtained by
G0W0 approximation. When I run a tddft calculation, using ALDA, or Bootstrap kernels, and put task="skip" inside the gw block, the dielectric function doesn't shift, but in BSE calculation it shifts. This means that in tddft calculations the eigenvalues are read from the Kohn-Sham ones. Could anyone help me to perform a tddft calculation on top of G0W0 results?

kind regards
M. Tarighi
Malek-Ashtar university, Iran

Can Spontaneous Polarization be calculated with the help of DFT based FPLO or is there any interphase of Berry phase calculations and FPLO?

Spontaneous Polarization calculations by FPLO by Sapna Singh (guest), 17 Jan 2017 12:41

Dear Ahmad,

I run your input with mpi parallelization over 16 processors and it worked. Maybe you can try with the same setup.

Best regards,
Caterina Cocchi
(exciting team)

1 node : 20 cores (40 threads) (2 * Intel(R) Xeon(R) CPU E5-2687W v3) + 120 GB RAM

parallelization: smp

ifort, icc and mkl (intel parallel studio 2013_sp1_update3)

mpich2 1.4.1p1

fftw 3.3.4

Dear Ahmad,

which parallelization setup (how many processors distributed on how many nodes) did you use in the problematic calculation?

Best regards,
Caterina Cocchi
(exciting team)

Dear Caterina

Thank you, but as I said in the first post, when I run all sections at the same time It progresses well.
I run these calculations with a 40 core and 120GB RAM computer and after two weeks there was not any progress.
I've converged XANES spectra for different k-meshes.

There is another job on this system now and I will check it again later.
By the way, I truly appreciate you caring about my job.

Best Regards
Ahmad

Dear Ahmad,

exciting works perfectly with your input file. Indeed, it takes a lot of time to perform the first task of BSE, namely the calculation of Kohn-Sham eigenvalues and eigenvectors with the parameters set in the xs block. This is due to the very large shifted k-mesh (16x16x1) that you chose. The calculation is not stuck. In your working directory you should see files updating continuously. If you reduce the k-mesh, the calculation should obviously speed up.

I hope these suggestions will solve your problem.

Best regards,
Caterina Cocchi
(exciting team)

Dear Caterina

Here is my input file:

<input>
   <title>phosphorene</title>
   <structure autormt="true" speciespath="/opt/exciting/carbon/species">
      <crystal scale="1">
         <basevect>6.277084      0.000000     0.000000</basevect>
         <basevect>0.000000      8.606720     0.000000</basevect>
         <basevect>0.000000      0.000000     32.125344</basevect>
      </crystal>
      <species speciesfile="P.xml" >
         <atom coord="0.99912200   0.41325505   0.26718847" />
         <atom coord="0.99913000   0.58674519   0.14238404" />
         <atom coord="0.49911300   0.08674939   0.26719053" />
         <atom coord="0.49912100   0.91325037   0.14238198" />
      </species>
   </structure>

   <groundstate 
      do="skip" 
      vdWcorrection="TSvdW"
      rgkmax="8"  
      ngridk="8 8 1"  
      xctype="GGA_PBE">
   </groundstate>

   <xs  
      xstype="BSE"  
      ngridk="16 16 1"  
      vkloff="0.05 0.15 0.25"  
      ngridq="16 16 1"  
      nempty="50"  
      gqmax="3.99"  
      broad="0.018"  
      tevout="true" >

      <energywindow  
         intv="75.4 78.4"  
         points="1500" />

      <screening  
         screentype="full"  
         nempty="100" />

      <BSE  
         xas="true"  
         xasspecies="1"  
         xasatom="1"  
         xasedge="L23"  
         bsetype="singlet"  
         nstlxas="1 30" />

      <qpointset>
         <qpoint>0.0 0.0 0.0</qpoint>
      </qpointset>

   </xs>

</input>

Do you also have any offer to get a better result?

Best wishes
Ahmad

Dear Ahmad Abdolmaleki,

could you please post here the input file of the calculation that gives you the mentioned problem?

Best regards,
Caterina Cocchi
(exciting team)

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