[lammps-users] How to create amorphous structure

Dear all,
I am trying to do a simulation of the amorphous structure of nanoparticle. Please can you tell me how to create an amorphous structure using LAMMPS? Since I am creating and simulation box and creating a region for filling the atoms. But when i am creating atoms using “create_atom” random and “lattice none” but we have to specify the number of atoms for this command. But number Of atoms and region size is not compatible perfectly.
If you didn’t understand my question then please let me know, I will improve my question.

Thanking you

Kishan sidh

yes, please improve your question.

the situation is quite simple: when you create atoms on lattice points, the number of atoms is defined by the choice of lattice and the region, when you create atoms in random positions, no such constraint exists and thus you must specify the number of atoms you want to be created. usually that number will be determined from the desired density you want to model.

in general, for creating an amorphous structure there are two strategies:

  • create atoms on lattice positions (density is determined by the choice of lattice constant), then melt and run at a sufficiently high temperature to randomize the positions and quench to the desired temperature and relax.
  • create atoms on random positions at desired density and carefully overlap and relax and then equilibrate at the desired temperature.

both methods have benefits and disadvantages.