How to find the values of DFTD3 parameters?
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 Newbie
 Posts: 13
 Joined: Sat Dec 04, 2021 6:43 am
How to find the values of DFTD3 parameters?
Hi everyone,
This is my first time using the DFTD3 method with GGA functional for a magnetic heterostructure. The calculation works well if I don't consider the vdW correction (standard DFT) but crashes if DFTD3 is included. I tried with IDW=11 and IVDW=12 but it got crashed. Then I found that I should also mention VDW_A1, VDW_A2, and VDW_S8 in the INCAR file. But there is no clear explanation of how to set them on vasp wiki. I found their values in one of the posts here and I used them but still, the calculation didn't converge. I tried with ALGO=Normal and ALGO=All but none of them worked. Attached is my INCAR file, I would appreciate it if anyone could help me find the right values of DFTD3 parameters. Or is there anything missing in my INCAR file for DFTD3 calculations?
ISTART = 0
ICHARG = 2
GGA = PE
IVDW = 12
VDW_A1 = 0.4289
VDW_A2 = 4.4407
VDW_S8 = 0.7875
LDAU = .TRUE.
LDAUTYPE = 2
LDAUL = 2 2 1 1 1
LDAUU = 4.0 3.0 0.0 0.0 0.0
LDAUJ = 0.0 0.0 0.0 0.0 0.0
LMAXMIX = 4
NPAR = 4
KPAR = 4
PREC = Normal
ALGO = All
ENCUT = 400
EDIFF = 1.0E7
LORBIT = 11
LREAL = F
GGA_COMPAT = .FALSE.
ADDGRID = .FALSE.
NSW = 500
EDIFFG = 1.0E2
ISIF = 4
IBRION = 2
POTIM = 0.015
SYMPREC = 1.0E6
ISYM = 0
AMIX = 0.1
BMIX = 0.00001
AMIX_MAG = 0.4
BMIX_MAG = 0.00001
MAXMIX = 40
ISMEAR = 0
SIGMA = 0.03
ISPIN = 2
MAGMOM = 3*4.5 2*3.6 2*0.5 6*0.5 12*0.5 6*0.5
Thank you in advance.
Roma
This is my first time using the DFTD3 method with GGA functional for a magnetic heterostructure. The calculation works well if I don't consider the vdW correction (standard DFT) but crashes if DFTD3 is included. I tried with IDW=11 and IVDW=12 but it got crashed. Then I found that I should also mention VDW_A1, VDW_A2, and VDW_S8 in the INCAR file. But there is no clear explanation of how to set them on vasp wiki. I found their values in one of the posts here and I used them but still, the calculation didn't converge. I tried with ALGO=Normal and ALGO=All but none of them worked. Attached is my INCAR file, I would appreciate it if anyone could help me find the right values of DFTD3 parameters. Or is there anything missing in my INCAR file for DFTD3 calculations?
ISTART = 0
ICHARG = 2
GGA = PE
IVDW = 12
VDW_A1 = 0.4289
VDW_A2 = 4.4407
VDW_S8 = 0.7875
LDAU = .TRUE.
LDAUTYPE = 2
LDAUL = 2 2 1 1 1
LDAUU = 4.0 3.0 0.0 0.0 0.0
LDAUJ = 0.0 0.0 0.0 0.0 0.0
LMAXMIX = 4
NPAR = 4
KPAR = 4
PREC = Normal
ALGO = All
ENCUT = 400
EDIFF = 1.0E7
LORBIT = 11
LREAL = F
GGA_COMPAT = .FALSE.
ADDGRID = .FALSE.
NSW = 500
EDIFFG = 1.0E2
ISIF = 4
IBRION = 2
POTIM = 0.015
SYMPREC = 1.0E6
ISYM = 0
AMIX = 0.1
BMIX = 0.00001
AMIX_MAG = 0.4
BMIX_MAG = 0.00001
MAXMIX = 40
ISMEAR = 0
SIGMA = 0.03
ISPIN = 2
MAGMOM = 3*4.5 2*3.6 2*0.5 6*0.5 12*0.5 6*0.5
Thank you in advance.
Roma

 Global Moderator
 Posts: 86
 Joined: Mon May 08, 2023 4:08 pm
Re: How to find the values of DFTD3 parameters?
Hi Roma,
It is difficult to analyze the problem without further information. Please, provide all the relevant input and output files in accordance with the forum posting guidelines.
It is difficult to analyze the problem without further information. Please, provide all the relevant input and output files in accordance with the forum posting guidelines.
Manuel
VASP developer
VASP developer

 Newbie
 Posts: 13
 Joined: Sat Dec 04, 2021 6:43 am
Re: How to find the values of DFTD3 parameters?
Hi Manuel,
Thank you for your reply. The attached zip file contains the input files as well as vasp.out file.
Thank you.
Thank you for your reply. The attached zip file contains the input files as well as vasp.out file.
Thank you.
You do not have the required permissions to view the files attached to this post.

 Global Moderator
 Posts: 86
 Joined: Mon May 08, 2023 4:08 pm
Re: How to find the values of DFTD3 parameters?
As far as I can tell, there is nothing wrong with your INCAR file. The DFTD3 parameters are explained on this site on the VASP wiki. As you can see, default values are already provided for the standard PBE functional. They are identical to the values you specified.
The error in the standard output and the number of iterations indicates that the calculation might already be converged. Please check the forces of your last ionic step in the OUTCAR file to confirm that this is the case. If the calculation is well converged already, you may proceed by copying CONTCAR to POSCAR and restarting the calculation with IBRION=1. According to this forum post, you can try to set ADDGRID=true and specify a larger ENCUT in this final step.
The error in the standard output and the number of iterations indicates that the calculation might already be converged. Please check the forces of your last ionic step in the OUTCAR file to confirm that this is the case. If the calculation is well converged already, you may proceed by copying CONTCAR to POSCAR and restarting the calculation with IBRION=1. According to this forum post, you can try to set ADDGRID=true and specify a larger ENCUT in this final step.
Manuel
VASP developer
VASP developer

 Newbie
 Posts: 13
 Joined: Sat Dec 04, 2021 6:43 am
Re: How to find the values of DFTD3 parameters?
Hi Manuel,
Thank you for the suggestion. However, I have already tried this and found that this method doesn't work. Every time I get the same energy pattern and the same error.
In fact, if you look at the energy pattern, it first tries to converge but after several ionic steps, it diverges and gives the random energy. The attached file contains the energies in each ionic as well as electronic steps. I also checked the XDATCAR file. It shows that after some ionic steps, the vdW distance between two monolayers starts decreasing and they come closer and closer, and eventually, they overlap with each other. From this point, the VASP starts throwing random energy values. Does this mean the heterostructure is not stable?
There is no issue with the standard DFT method. This is weird. Do you think EDIFF = 1E6 and ENCUT = 350 are tight enough to have this issue? Does it make sense if I further lower both parameters?
I also have attached the XDATCAR file for reference.
Thank you.
Thank you for the suggestion. However, I have already tried this and found that this method doesn't work. Every time I get the same energy pattern and the same error.
In fact, if you look at the energy pattern, it first tries to converge but after several ionic steps, it diverges and gives the random energy. The attached file contains the energies in each ionic as well as electronic steps. I also checked the XDATCAR file. It shows that after some ionic steps, the vdW distance between two monolayers starts decreasing and they come closer and closer, and eventually, they overlap with each other. From this point, the VASP starts throwing random energy values. Does this mean the heterostructure is not stable?
There is no issue with the standard DFT method. This is weird. Do you think EDIFF = 1E6 and ENCUT = 350 are tight enough to have this issue? Does it make sense if I further lower both parameters?
I also have attached the XDATCAR file for reference.
Thank you.
You do not have the required permissions to view the files attached to this post.

 Global Moderator
 Posts: 86
 Joined: Mon May 08, 2023 4:08 pm
Re: How to find the values of DFTD3 parameters?
My best guess at this point is that the calculation is not accurate enough.
Here are some parameters you can play around with to increase accuracy:
Here are some parameters you can play around with to increase accuracy:
 Increase ENCUT (350 eV is rather low)
 Decrease EDIFF and/or EDIFFG
 Set PREC=accurate
 POTIM (try lowering to maybe 0.01)
Manuel
VASP developer
VASP developer

 Newbie
 Posts: 13
 Joined: Sat Dec 04, 2021 6:43 am
Re: How to find the values of DFTD3 parameters?
I was able to run the calculations successfully by changing the number of cores or running the calculations on a separate cluster. The problem seems to be related to the parallelization. It is interesting that the same input setting works for DFT, but not for DFTD3. I still have no idea how this happened.
Anyway, thank you so much for the help.
Anyway, thank you so much for the help.

 Newbie
 Posts: 1
 Joined: Wed Nov 17, 2021 2:03 am
Re: How to find the values of DFTD3 parameters?
Hello there, I have the same problem, VASP crashes for large systems whenenver IVDW = 12 is applied.
Have you found any soulutions? Many thanks!
Have you found any soulutions? Many thanks!

 Global Moderator
 Posts: 86
 Joined: Mon May 08, 2023 4:08 pm
Re: How to find the values of DFTD3 parameters?
Hi,
I'm happy to look into the matter. If your issue is directly related to the original post, then we can remain in this topic. Otherwise, I would encourage you to open a new separate topic in the forum. In any case, I would ask you to provide more information by uploading the input and output files according to our forum posting guidelines.
I'm happy to look into the matter. If your issue is directly related to the original post, then we can remain in this topic. Otherwise, I would encourage you to open a new separate topic in the forum. In any case, I would ask you to provide more information by uploading the input and output files according to our forum posting guidelines.
Manuel
VASP developer
VASP developer