 MEAM: Modified Embedded Atom Method 
Definition:  A method to
approximate the
total energy of a
random arrangement
of atoms. 
Explanation:  As in
embedded atom method
(→EAM),
the energy of atomic
arrangement is
given by a sum of
electrostatic pair
terms and an
embedding function
which describes the
local energy
density.
Equivalent to
density functional
theory (→DFT),
MEAM
describes the system
as a function of
electron density,
but uses the
approximation that
the density of the
whole system is a
simple superposition
of the local atomic
densities.
In addition to
EAM,
an explicit three
body
term is included to
improve the
potentials
description of
materials with
highly directional
bonds. This also
indirectly implies a
range of the
potential including
the next
nearest atom
neighbors, which may
improve accuracy,
but
increases
calculation time.
MEAM is three to
five times
slower than EAM.
The total energy
form for the MEAM
potential is given
in the equation
below, where φ_{ij}(r_{ij})
is the pair
potential term
describing
electrostatic
corecore repulsion,
and
the cohesive
term, F_{i}(n_{i}),
describes the
energy gain of the
ion core when it is
embedded in the
energy density,
n_{i},
which is the
superposition of the
local energy
densities ρ_{j}(r_{ij})
and the three body
term.
The three body term
influences the
electron density
through the
dependence of
f_{ij}(r_{ij})
and g_{i}(cosθ_{jik}). 
Picture / Figure / Diagram: 



Gammasurface of an Al MEAM potential.


SFBLink:  The MEAM is used in molecular dynamics (→MD) simulations in part project A6 to determine grain boundary mobility. 
References:  Baskes, Phys Rev B, 46, 27272742, 1992 

