Unpublished potential developed by Xiaowang Zhou (Sandia) and included with LAMMPS in Sept, 2010. Note that the original file referred to Iodine as "Id". For the KIM version, this has been changed to the more standard "I".
Note that the potential gives slightly different results depending on which elements are read from the parameter file. For example, one can simulate a CsCl crystal by reading in either all 9 elements, or only Cs and Cl. These two alternatives produce a difference in the lattice constant of CsCl at the 10th significant figure, and in the cohesive energy at the 12th significant figure.
For the KIM Simulator Model, all elements are read in for all tests.
More information from the LAMMPS user group (posted by Steve Plimpton, Tue, 31 Aug 2010 18:47:02 -0600):
Xiaowang Zhou (Sandia) has added his
embedded ion method (EIM) potential to LAMMPS.
It's the 5 Sept 10 patch.
This enables modeling of ionic compounds, with
a potential file for 9 elements: Li, Na, K, Rb, Cs, F, Cl, Br, and I.
Systems with any combination of these elements can be modeled.