Dear users,
I am try to calculate Dynamic matrix by LAMMPS , by moving the atoms at ( ±x,±y,±z ) direction by using the following equation
But the phonon transmission going to zero ,
Anyone can help me to find the coupling matrix of the reference cell to its two neighbouring cells in a wire as shown below
With best wishes,
Alaa,
image001.emz (7.76 KB)
This tool may make the task simpler, if you aren’t constrained to only using LAMMPS.
https://nanochemistry.curtin.edu.au/gulp/overview.cfm
Respectfully,
Dear Casimir,
Thank you for your message,
I fact I wrote Fortran code to greate dynamic matrix 3n x 3n where n no. of atoms by using the LAMMPS output file by using the flag “displace_atoms atom_i6 move 0.01 0.00 0.00 units box
dump 1 g2 custom 1 dump_i6xp.fc id type fx fy fz
dump_modify 1 sort id
dump_modify 1 format “%d d .12f .12f .12f”
run 0”
I think the tools that you indicate more complicate
Cheers,
Alaa,
Dear users,
I am try to calculate Dynamic matrix by LAMMPS , by moving the atoms at (
+-x,+-y,+-z ) direction by using the following equation
why not use fix phonon?
http://lammps.sandia.gov/doc/fix_phonon.html
axel.
Dear Axel ,
I am never use fix phonon , and I think it is difficult to use it .
Thanks,
Alaa,
Dear Axel ,
I am never use fix phonon , and I think it is difficult to use it .
if you don't want to use existing functionality, and also don't know how
to follow through on your method of choice, then you are out of luck.
Dear axel,
The Idea I want to make compare between LAMMPS and DFT ,for example I got force constant by lammps and force constant by DFT (siesta). my job is which one more accuracy , I think it is difficult to use DFT in fix phonon
If you have any other idea help me
Cheers,
Alaa,
Dear axel,
The Idea I want to make compare between LAMMPS and DFT ,for example I got
force constant by lammps and force constant by DFT (siesta). my job is
which one more accuracy , I think it is difficult to use DFT in fix phonon
you are not making much sense here. it is obvious that your problem is
not as such a LAMMPS problem, but seems to be more a problem of
understanding what you are doing. nobody here is likely to do your job for
you and just hand you the answer.
If you have any other idea help me
i don't know how to help people that don't make sense to me.
Many thanks Axel,