Axially symmetric molecules
In general, the intermolecular pair potential for axially symmetric molecules,
, is a function of five coordinates:
![{\displaystyle \left.\Phi _{12}\right.=\Phi _{12}(r,\theta _{1},\phi _{1},\theta _{2},\phi _{2})}](https://wikimedia.org/api/rest_v1/media/math/render/svg/6a48c27be9d00f30eab3554b6150b3021013283d)
The angles
and
can be considered to be polar angles, with the
intermolecular vector,
, as the common polar axis. Since the molecules
are axially symmetric, the angles
do not influence the value of
.
A very powerful expansion of this pair potential is due to Pople (Ref. 1 Eq. 2.1):
,
where
are the spherical harmonics.
See also
References
- J. A. Pople "The Statistical Mechanics of Assemblies of Axially Symmetric Molecules. I. General Theory", Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences 221 pp. 498-507 (1954)