OPTIMIZATION OF POTENTIALS FUNCTIONAL FORMS WITHIN THE MODIFIED EMBEDDED ATOM METHOD FROM SELECTED FIRST PRINCIPLES DATA.

Ramon Ravelo

Department of Physics

University of Texas

El Paso, TX 79968

and

Applied Physics Division

Los Alamos National Laboratory

Los Alamos, NM 87545

The modified embedded atom method (MEAM) is an empirical extension of the embedded atom method (EAM) that includes angular forces by the incorporation into the model of a screening function and a expansion of the electron density in multi-poles. This potential model has been gaining popularity in the scientific community due to its flexibility and ability to describe many crystals structures as well as both covalent and metallic bonding within the same description. The model comprises 11 adjustable parameters and 5 functional forms which are input into the model as ''guess'' functions. We will present a formalism which makes use of appropriate first principles calculations

to systematically obtain the functional forms of the partial electron densities. As a test of the method we develop a MEAM model of Fe and compared its predictive accuracy with other existing models.