Ds. Kosov et Pla. Popelier, Convergence of the multipole expansion for electrostatic potentials of finite topological atoms, J CHEM PHYS, 113(10), 2000, pp. 3969-3974
The exact atomic electrostatic potential (AEP) and atomic multipole moments
are calculated using the topological partitioning of the electron density.
High rank (l less than or equal to 20) spherical tensor multipole moments
are used to examine the convergence properties of the multipole expansion.
We vary independently the maximum multipole rank, l(max), and the radius of
the spherical grid around an atom in a molecule where we measure the discr
epancy between the exact AEP and the one obtained via multipole expansion.
The root mean square values are between 0.1 and 1.6 kJ/mol for four atoms (
C, N, O, S) on a spherical grid with the rho=0.001 a.u. convergence radius
and for l(max)=4. Our calculations demonstrate that this fast convergence i
s due to the decay of the electron density. We show that multipole moments
generated by finite atoms are adequate for use in the multipole expansion o
f the electrostatic potential, contrary to some claims made in the literatu
re. Moreover they can be used to model intermolecular and in principle intr
amolecular interactions as well. (C) 2000 American Institute of Physics. [S
0021-9606(00)31734-2].