compute angle\local

Hi,

I want to calculate the angle distribution, similar to the one in the attached Figure.tif taken from

K. Vollmayr, W. Kob, and K. Binder, J. Chem. Phys. 105, 4714 ,1996.

My system is a 19,652 atoms with lj potential under constant temperature of 70K and pressure of 100 bar.

I read in the documentation that I need to produce a list of angles to create that angle distribution,

which is where the problem lies in. The dump file doesn’t contain the angle and the atom triplets

associated with the angle.

below is the script and a dump file, can you please point me to the problem in my script ?

Thank you

Figure.tif (42 KB)

Hi,

I want to calculate the angle distribution, similar to the one in the
attached Figure.tif taken from

K. Vollmayr, W. Kob, and K. Binder, J. Chem. Phys. 105, 4714 ,1996.

My system is a 19,652 atoms with lj potential under constant temperature of
70K and pressure of 100 bar.

I read in the documentation that I need to produce a list of angles to
create that angle distribution,

which is where the problem lies in. The dump file doesn't contain the angle
and the atom triplets

associated with the angle.

below is the script and a dump file, can you please point me to the problem
in my script ?

the problem is, that you don't have any _topological angles_, i.e.
angles in your system that are part of the force field.
compute angle/local can only show you those and they have to be
defined in a data file.

what you seem to want to compute, however, is a histogram of angles
from atom triplets of nearest neighbors.
that is a completely different computation, somewhat similar to what
compute rdf does for pairwise distances.
if you want to do this from within LAMMPS, you would have to program a
new compute.

axel.