Embedded Atom Method

The embedded atom model ( English embedded atom model ), in short: EAM is to calculate a method that allows the total energy of any arrangement of atoms in a metal approximation. The energy of such an arrangement is given by a sum of purely electrostatic pair terms and an embedding function that describes the local electron density .

Just as with density functional theory (DFT), this description makes use of the fact that the energy of a system can be described as a functional of the electron density. The embedded atom method, however, makes the approximation that the density of the overall system can be described simply as a superposition of local atomic density functions. EAM is related to the tight-binding theory approach .

Energy function

The total energy can therefore be written as follows:

${\displaystyle E_{\mathrm {tot} }=\sum _{i}F(\rho _{i})+{\frac {1}{2}}\sum _{i\neq j}\phi (r_{ij})}$,

where is the distance between atom and is the pair potential function for electrostatics and the local electron density at the location of is with the embedding function . ${\displaystyle r_{ij}}$ ${\displaystyle i}$ ${\displaystyle j}$ ${\displaystyle \phi (r)}$ ${\displaystyle \rho _{i}}$ ${\displaystyle i}$ ${\displaystyle F}$

For a single element system, three functions are required in an EAM description. The embedding function, the electron density function and the pair interaction potential. These functions are mostly determined by fitting experimental and ab initio data. For example, one can assume the functional form of a Lennard-Jones potential for the pair interaction and fit this to data from DFT calculations for the corresponding system.

Individual evidence

1. ↑ Murray S. Daw, MI Baskes: Embedded-atom method: Derivation and application to impurities, surfaces, and other defects in metals . In: Physical Review B . tape 29 , no. 12 , June 15, 1984, pp. 6443-6453 , doi : 10.1103 / PhysRevB.29.6443 .
2. ↑ Chol-Jun Yu: Atomistic Simulations for Material Processes Within Multiscale Method. (PDF; 2.0 MB) Retrieved April 20, 2010 .