Hello everyone,

I use the command ‘compute 1 all cna/atom 3.0855’ to observe the local

structure of my model. But I find the data of initial structure I build in

output file are not ‘1’ which means fcc, there are a lot of ‘5’ means

unknown. Are there any errors in my in file code?

Hello everyone,

I use the command 'compute 1 all cna/atom 3.0855' to observe the local

structure of my model. But I find the data of initial structure I build in

output file are not '1' which means fcc, there are a lot of '5' means

unknown. Are there any errors in my in file code?

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

part of my in file code is as follow:

units metal

boundary p p p

atom_style atomic

lattice fcc 3.6147

region whole block 0.0 10.0 0.0 10.0 0.0 10.0 units box

create_box 1 whole

create_atoms 1 region whole

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

Furthermore, if I delete 'units box', which means the unit is based on

lattice. The new initial structure checked by cna/atom command is right!

All are fcc=1!

yes, this makes perfect sense. at 10 angstrom edge length,

your box and region is not commensurate with your fcc lattice

spacing and thus you have mismatches at the periodic boundaries

resulting in an "unknown" coordination.

Then I'd like to build a coherent twin boundary in the middle of my cube

model. Combine the left and right part. As below:

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

# the whole box

lattice fcc 3.6147

region whole block 0.0 10.0 0.0 10.0 0.0 10.0

create_box 1 whole

create_atoms 1 region whole

# left part

region left block 0.0 5.0 INF INF INF INF

lattice fcc 3.6147 orient x -1 1 -1 orient y -1 1 2 orient z 1 1 0

create_atoms 1 region left

# right part

region right block 5.0 10.0 INF INF INF INF

lattice fcc 3.6147 orient x 1 -1 1 orient y -1 1 2 orient z -1 -1 0

create_atoms 1 region right

# delete overlap atoms

delete_atoms overlap 0.275 left right

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

Based on the code I write above, I cannot obtain the model I want. I don't

know why?

first you fill the *entire* box with atoms, *then* you

place a set of atoms on the left and on the right

half. that makes no sense. why the first create_atoms??

axel.