# [lammps-users] Calculating energy of grain boundary and geometry of it

Hello

Excuse me,

I wrote my code with use https://icme.hpc.msstate.edu/mediawiki/index.php/LAMMPS_Help3.

So then, I have few questions?

First my question is when we want to calculate the area of grain boundary, we multiply 2 in formula. I cannot figure out, why multiply 2 in formula? (For instance: LxLz2)

And also second my question is energy of my model is obtained extremely higher in comparison with existing articles. Therefore it causes energy of grain boundary increase. Can you help me? What should I do?

The last my question is, I think, I must identify the grain boundary region for obtaining energy of grain boundary. As a result, I have defined region for grain boundary like this

· lattice fcc 3.6150

· region main block 0.00000 30 -15 15 0.00000 1 units lattice

· create_box 2 main

· region down block INF INF -15 0.00000 INF INF units lattice

· lattice fcc 3.6150 orient x 1 -3 0 orient y 3 1 0 orient z 0 0 1

· create_atoms 1 region down

· region up block INF INF 0.00000 15 INF INF units lattice

· lattice fcc 3.6150 orient x -1 -3 0 orient y 3 -1 0 orient z 0 0 1

· create_atoms 2 region up

· region grainboundary block INF INF -1 1 INF INF units lattice

· group 1 region down

· group 2 region up

· group 3 region grainboundary

Then I try to calculate the energy of the grain boundary using this region. I want to know, is this my job true?

And in the end, I have attached my cod to this mail. I will have been so pleasure if you are leading me.

Appreciatively

Vahed

input.txt (4.31 KB)

log.lammps (40.9 KB)

Hello

Excuse me,

I wrote my code with use https://icme.hpc.msstate.edu/mediawiki/index.php/LAMMPS_Help3.

sorry, but that URL does not seem to link to an existing page.

So then, I have few questions?

First my question is when we want to calculate the area of grain boundary, we multiply 2 in formula. I cannot figure out, why multiply 2 in formula? (For instance: LxLz2)

you will have an interface on both sides of your regions, do you not?

And also second my question is energy of my model is obtained extremely higher in comparison with existing articles. Therefore it causes energy of grain boundary increase. Can you help me? What should I do?

what energy exactly are you talking about? and what are you comparing two?

the first rule of science is to be precise in what you describe.

The last my question is, I think, I must identify the grain boundary region for obtaining energy of grain boundary. As a result, I have defined region for grain boundary like this

· lattice fcc 3.6150

· region main block 0.00000 30 -15 15 0.00000 1 units lattice

· create_box 2 main

· region down block INF INF -15 0.00000 INF INF units lattice

· lattice fcc 3.6150 orient x 1 -3 0 orient y 3 1 0 orient z 0 0 1

· create_atoms 1 region down

· region up block INF INF 0.00000 15 INF INF units lattice

· lattice fcc 3.6150 orient x -1 -3 0 orient y 3 -1 0 orient z 0 0 1

· create_atoms 2 region up

· region grainboundary block INF INF -1 1 INF INF units lattice

· group 1 region down

· group 2 region up

· group 3 region grainboundary

Then I try to calculate the energy of the grain boundary using this region. I want to know, is this my job true?

please note that this is not really a question about LAMMPS but about doing your research correctly. it is not the job of this mailing list to approve of your inputs. if you have questions about or need help with your research then you need to discuss this with your adviser/supervisor/tutor.

axel.