Messages

1

General Questions and Answers / Re: General question about total energy in ATK

« on: March 24, 2021, 16:17 »

Thank you very much for the response.

2

General Questions and Answers / General question about total energy in ATK

« on: March 22, 2021, 13:08 »

Dear all,

I have a very basic question. If I optimize the same structure in two different situations (for example two molecules next to each other, first time with one specific orientation against each other and next time again the same molecules with a different orientation against each other), and I calculate the total energy in two cases, let's assume for the first case I get -50 eV and for the second one I get -55eV. Now I want to use these figures to say which orientation is more stable. How can I say that? I mean the sign of the total energy confuses me. I know that the one with less total energy is more stable, but with considering the negative sign or not? (-55 < -50 but |-55|>|-50|)?

Thanks

3

General Questions and Answers / Re: Absorption coefficient

« on: March 22, 2021, 12:52 »

Hi,

You can calculate the opticalspectrum: https://docs.quantumatk.com/manual/Types/OpticalSpectrum/OpticalSpectrum.html.

Best regards,

4

General Questions and Answers / Re: ±isovalue option meaning in visualizing molecular orbitals

« on: February 25, 2021, 14:28 »

Thanks

5

General Questions and Answers / ±isovalue option meaning in visualizing molecular orbitals

« on: February 23, 2021, 10:17 »

Dear all,

When I visualize molecular orbitals (for example HOMO or LUMO), when I tick the ±isovalue option, the orbitals will be shown with two colors red and blue. What do these colors mean? what is the difference between blue and red regions?

Thanks

6

General Questions and Answers / Re: Problem in finding HOMO-LUMO because of partial occupations

« on: February 22, 2021, 19:45 »

Anyone to help me please?
I think the problem is the number of electrons. The number of electrons for the solo slab is 1080 and for the solo molecule is 58, but for the whole structure is 1138.4 !!!
Thanks

7

General Questions and Answers / Problem in finding HOMO-LUMO because of partial occupations

« on: February 22, 2021, 12:24 »

Dear all,

How can I determine HOMO-LUMO for this structure? there are some partial occupations in some orbitals! the script and the molecular energy spectrum have been attached.

 562  -1.457714e+00   2.000000e+00
  563  -1.396535e+00   2.000000e+00
  564  -2.405055e-01   1.999818e+00
  565  -7.608169e-02   1.899860e+00
  566   2.848218e-02   4.988281e-01
  567   3.148024e-01   1.029389e-05
  568   3.187673e-01   8.830246e-06
  569   3.190502e-01   8.734142e-06
  570   5.065160e-01   6.193482e-09
  571   5.070444e-01   6.068169e-09

Thanks
Best regards,

8

General Questions and Answers / Re: Bandstructure by using DFT+U

« on: February 12, 2021, 15:42 »

I checked several papers and all of them use plane wave, but as far as I know, U correction is not possible for the plane wave method in ATK. What do you suggest me to do? thanks.

9

General Questions and Answers / Re: Bandstructure by using DFT+U

« on: February 12, 2021, 15:35 »

Thank you very much for your response. How should I do that? I mean how can I make a good guess for the beginning? I am totally blind for starting with what quantities of U and for what orbitals
Thanks

10

General Questions and Answers / Bandstructure by using DFT+U

« on: February 12, 2021, 11:25 »

Dear ATK staff,

I am trying to calculate the ZnO bandstructure by using the GGA PBE + U method as it has been done in this paper: Ferromagnetism properties of Er-doped ZnO:a GGA +Ustudy (https://doi.org/10.1039/C6RA17921E)
I changed the lattice parameters to a=3.32 and c=5.34 which are the optimized numbers in the paper and selected 7 eV and 10.5 eV as U for oxygen and zinc atoms. Everything is similar to the ones in the paper but I can not calculate the bandstructure and the bandgap is 0 for my calculations. I attached the script and the log and the result. Would you please help me solve this problem?

Thanks.

11

General Questions and Answers / Re: Export images in vector format

« on: January 28, 2021, 16:28 »

Okay, thanks alot.

12

General Questions and Answers / Export images in vector format

« on: January 26, 2021, 11:03 »

Hi all,
Is there any way to export images from "viewer" in any vector format?
Thanks.
Hadi

13

General Questions and Answers / Re: Asking for help; I can not relax a ZnO surface!

« on: January 21, 2021, 12:38 »

The problem has been solved. The 0001 ZnO surface is not stable and needs some modifications to become stable. Just to share what I found out: if anyone is interested in more info, he/she may take a look at the following paper:
http://dx.doi.org/10.1016/j.susc.2012.09.004

Thanks,
Hadi

14

General Questions and Answers / Re: Slater-Koster method for charge transfer calculations

« on: January 20, 2021, 15:38 »

Thank you very much for your response. I will do so. Sorry, I asked a new question titled "Asking for help; I can not relax a ZnO slab". Would you mind checking it to help me, please? It has been a week I am trying to solve that problem. Thank you for being supportive

15

General Questions and Answers / Asking for help; I can not relax a ZnO surface!

« on: January 20, 2021, 10:02 »

Dear all,

I am trying to relax ZnO (10-10),(11-20), and (0001) slabs by using the semiempirical method, Slater-Koster. For (10-10) and (11-20) the calculations are fast and the surfaces are stable and in a good form and everything is reasonable. However, for the (0001) slab, I tried several slabs with different sizes and boundary conditions but the calculations will converge in a very long time (2-3 days!!!) while the surface finally collapses or deforms. I attached the script and a pic. Would you please guide me on what the problem could be and what the solution is? I have been struggling with this for one week, trying any solution I assumed may work 
Thanks.

Hadi