This thread is locked.Only browsing is available.
Top Page > Browsing
Silicon cd force calculations
Date: 2012/08/28 20:21
Name: Dariusz Chrobak   <dariusz.chrobak@gmail.com>

Dear All,

I encountered a small problem that concerns force calculations. My structure is a simple cubic diamond Si:

************************************************************

DATA.PATH /home/nhl/opt/openmx3.6/DFT_DATA11

System.Name d
level.of.stdout 1
level.of.fileout 3

Species.Number 1
<Definition.of.Atomic.Species
Si Si7.0-s2p2d1 Si_CA11
Definition.of.Atomic.Species>

Atoms.Number 8
Atoms.SpeciesAndCoordinates.Unit FRAC
<Atoms.SpeciesAndCoordinates
1 Si -0.50 -0.50 -0.50 2 2
2 Si 0.0 0.0 -0.50 2 2
3 Si 0.0 -0.50 0.0 2 2
4 Si -0.50 0.0 0.0 2 2
5 Si -0.25 -0.25 -0.25 2 2
6 Si 0.25 0.25 -0.25 2 2
7 Si 0.25 -0.25 0.25 2 2
8 Si -0.25 0.25 0.25 2 2
Atoms.SpeciesAndCoordinates>
Atoms.UnitVectors.Unit AU

<Atoms.UnitVectors
10.2612 0.0 0.0
0.0 10.2612 0.0
0.0 0.0 10.2612
Atoms.UnitVectors>

scf.restart off

scf.XcType LDA
scf.SpinPolarization off
scf.ElectronicTemperature 300.0
scf.energycutoff 160.0
scf.maxIter 100
scf.EigenvalueSolver band
scf.lapack.dste dstevx
scf.Kgrid 8 8 8
scf.Mixing.Type rmm-diisk
scf.Init.Mixing.Weight 0.010
scf.Min.Mixing.Weight 0.001
scf.Max.Mixing.Weight 0.200
scf.Mixing.History 15
scf.Mixing.StartPulay 5
scf.criterion 1.0e-7

orderN.HoppingRanges 6.0
orderN.NumHoppings 1

************************************************************

In the output file I found the following table of atomic forces:

************************************************************

<coordinates.forces
8
1 Si 2.71500 2.71500 2.71500 -0.000004654408 0.000000000007 -0.000000000004
2 Si 0.00000 0.00000 2.71500 -0.000004654413 0.000000000008 -0.000000000013
3 Si 0.00000 2.71500 0.00000 -0.000004654408 0.000000000014 -0.000000000006
4 Si 2.71500 0.00000 0.00000 -0.000004654419 0.000000000011 -0.000000000005
5 Si 4.07250 4.07250 4.07250 -0.000004654400 -0.000000000011 0.000000000003
6 Si 1.35750 1.35750 4.07250 -0.000004654397 -0.000000000005 0.000000000010
7 Si 1.35750 4.07250 1.35750 -0.000004654406 -0.000000000010 0.000000000007
8 Si 4.07250 1.35750 1.35750 -0.000004654401 -0.000000000014 0.000000000009
coordinates.forces>

************************************************************

They are asymetric so the question is siply why?

Thank you in advance for any comment.

BR, Darek
メンテ
Page: [1]

Re: Silicon cd force calculations ( No.1 )
Date: 2012/08/29 09:10
Name: T. Ozaki

Hi,

Thank you for your report.
We have also noticed it and identified that this comes from the calculation of
force(8) in Total_Energy.c. In fact, the numerical integration involved causes
the slight asymmetric force. The problem will be fixed in the next release.

Thank you.

Regards,

TO
メンテ
Re: Silicon cd force calculations ( No.2 )
Date: 2012/08/29 18:34
Name: Dariusz Chrobak  <dariusz.chrobak@gmail.com>

Hi,

Thank you for comment. I hope that this disfunctionality does not affect other important feautures of the openmx great software.

This is difficult to trace all relationships between parts of code for persons who are not developers.

Best regards,

Darek
メンテ

Page: [1]