Molecular charge densities and electrostatic interactions: a pseudoatom approach

Using Fourier transform techniques, the electrostatic interaction between Slater-type charge density functions is evaluated analytically thereby avoiding the use of numerical integration techniques and the bipolar expansion of absolute value r vector-r vector'-1. Electrostatic interactions between atoms of the first three rows of the Periodic Table were accurately described by Born-Mayer expressions ranging over several atomic units. Model studies of the N2-N2 interaction demonstrated the importance of penetration terms. At large separations when penetration terms can be neglected, pseudoatom point-multipole terms represented the electrostatic interaction more efficiently in general than molecular point-multipole terms