The Axilrod–Teller potential is a three-body potential that results from a third-order perturbation correction to the attractive London dispersion interactions (instantaneous induced dipole-induced dipole)
V
i
j
k
=
E
0
[
1
+
3
cos
γ
i
cos
γ
j
cos
γ
k
(
r
i
j
r
j
k
r
i
k
)
3
]
where
r
i
j
is the distance between atoms
i
and
j
, and
γ
i
is the angle between the vectors
r
i
j
and
r
i
k
. The coefficient
E
0
is positive and of the order
V
α
3
, where
V
is the ionization energy and
α
is the mean atomic polarizability; the exact value of
E
0
depends on the magnitudes of the dipole matrix elements and on the energies of the
p
orbitals.
