MD convergence bilayer

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MD convergence bilayer

Date: 2024/11/05 08:24
Name: Lillian: Dear Contributors,
I am having trouble of the MD convergence during geometry optimization. The scf process converged well, and the MD keeps reducing, however, it is still not converged after more than >800 iterations even after I reduce the criterion to 10^-4. Additionally, if I run from the restart file .dat#, it finishes only at the first MD iteration but it doesn't reach the convergence. My system is bilayer, and below I put the controllable parameters.

#
# SCF or Electronic System
#

scf.XcType GGA-PBE # LDA|LSDA-CA|LSDA-PW|GGA-PBE
scf.SpinPolarization off # On|Off|NC
scf.ElectronicTemperature 300.0 # default=300 (K)
scf.energycutoff 250 # default=150 (Ry)
#scf.Ngrid 8 8 1
scf.maxIter 100 # default=40
scf.EigenvalueSolver Band # DC|GDC|Cluster|Band
scf.Kgrid 16 8 1 # means n1 x n2 x n3
scf.ProExpn.VNA off # default=on
scf.Mixing.Type rmm-diisk # Simple|Rmm-Diis|Gr-Pulay|Kerker|Rmm-Diisk
scf.Init.Mixing.Weight 0.0010
scf.Min.Mixing.Weight 0.0001
scf.Max.Mixing.Weight 0.3000
scf.Mixing.History 60
scf.Mixing.StartPulay 80
scf.Mixing.EveryPulay 1
scf.criterion 1.0e-9 # default=1.0e-6 (Hartree)

MD.Type EF # Nomd|Opt|DIIS|NVE|NVT_VS|NVT_NH
MD.Opt.DIIS.History 15 # default=7
MD.Opt.StartDIIS 20 # default=5
MD.maxIter 1000 # default=1
MD.Opt.criterion 1.0e-4 # default=1.0e-4(Hartree/Bohr)

<MD.Fixed.Cell.Vectors
1 1 1
1 1 1
1 1 1
MD.Fixed.Cell.Vectors>

<MD.Fixed.XYZ
1 0 0 0
2 0 0 0
3 0 0 0
4 0 0 0
5 0 0 0
6 0 0 0
7 0 0 0
8 0 0 0
9 0 0 0
10 0 0 0
11 0 0 0
12 0 0 0
13 0 0 0
14 0 0 0
15 0 0 0
16 0 0 0
17 0 0 0
18 0 0 0
19 0 0 0
20 0 0 0
21 0 0 0
22 0 0 0
23 0 0 0
24 0 0 0
MD.Fixed.XYZ>

scf.dftD on # on|off, default=off
version.dftD 3 # 2|3, default=2
DFTD3.damp bj # zero|bj, default=bj
DFTD.Unit AU # Ang|AU
DFTD.rcut_dftD 100.0 # default=100 (DFTD.Unit)
DFTD.cncut_dftD 40 # default=40 (DFTD.Unit)
DFTD.IntDirection 1 1 1 # default=1 1 1 (1:on 0:off)

<DFTD.periodicity
1 1
2 1
3 1
4 1
5 1
6 1
7 1
8 1
9 1
10 1
11 1
12 1
13 1
14 1
15 1
16 1
17 1
18 1
19 1
20 1
21 1
22 1
23 1
24 1
DFTD.periodicity>

I am wondering if you could suggest me about the issue.

Thank you very much for your assistance.

Regards,
Lillian

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Re: MD convergence bilayer ( No.1 )

Date: 2024/11/05 12:45
Name: Lillian

Dear Contributors,
I forget to mention that the forces rise up again to 0.1 Hartree/Bohr after reaching 0.002 Hartree/Bohr.

I am looking forward to your response.

Regards,
Lillian

Re: MD convergence bilayer ( No.2 )

Date: 2024/11/05 22:38
Name: Naoya Yamagcuhi

Hi,

I can't say for sure since the details of the structure are not clear, but I think you should delete the following line.

```
scf.ProExpn.VNA off # default=on
```

>Additionally, if I run from the restart file .dat#, it finishes only at the first MD iteration but it doesn't reach the convergence.

If the number of MD iterations is more than the 1000 you set, you need to set `MD.maxIter` to 2000, for example, because the calculation will end immediately after one calculation.

Regards,
Naoya Yamaguchi

Re: MD convergence bilayer ( No.3 )

Date: 2024/11/06 10:50
Name: Lillian

Dear Yamaguchi-sensei,
Thank you very much for your response. I have deleted the line as you suggested and it does faster the calculation. It seems like my system needs larger iteration number as well.

Thank you again.

Regards,
Lillian

Re: MD convergence bilayer ( No.4 )

Date: 2024/11/06 14:16
Name: Lillian

Dear Yamaguchi-sensei,
May I know why does the scf.ProExpn.VNA affect the calculation performance even though it is already off ?

Regards,
Lillian

Re: MD convergence bilayer ( No.5 )

Date: 2024/11/06 23:15
Name: Naoya Yamaguchi

Dear Lillian,

>May I know why does the scf.ProExpn.VNA affect the calculation performance even though it is already off ?

The default value is `On`, and if it is `On`, Projector expansions are used instead of grids to describe neutral atom potentials.

Regards,
Naoya Yamaguchi

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