Greetings lammps community,

I am constructing eam/alloy potentials and have run into some bizarre issues. The format for these potentials is as follows:

F_x

rho_x

F_y

rho_y

phi_x

phi_xy

phi_y

Where x denotes one element and y denotes another element. F is the embedding energy, rho is the electron density and phi is the pair potential.

For the potentials I have constructed, in the above format, properties of element x are calculated correctly. However, properties of element y are not calculated correctly. Then, if the format is changed to:

F_y

rho_y

F_x

rho_x

phi_y

phi_yx

phi_x

Then properties of element y are calculated correctly. However, properties of element x are not calculated correctly.

To ensure my formatting was correct, I constructed a single element alloy potential of the form:

F_x

rho_x

F_x

rho_x

phi_x

phi_xx

phi_x

And this yields correct properties regardless of creating atoms of type 1 or type 2.

So, I believe my formatting is correct, in that I can reproduce certain properties correctly. My header section isnt the issue, nor are the “atomic number, mass, lattice constant, lattice type” lines.

I am unsure of what is happening to give these anomalous results. Any help or tips or things to check would be most welcome.

Thanks all.