Gaussian-based electrostatic model

A Gaussian-based electrostatic model (GEM) has been explored as an alternative to distributed point multipole electrostatic representation. GEM computes the molecular interaction energies using an approach similar to SIBFA... 

Status of the Gaussian Electrostatic Model, a Density-Based Polarizable Force Field... 

The static dipole polarizabilities of alkali dimers have been calculated as a function of the internuclear distance and of the vibrational index for both their electronic ground state and lowest triplet state. The method is based on /-dependent pseudopotentials for atomic core representation, Gaussian basis sets, effective core potentials to account for core polarization, the evaluation of molecular orbitals by the restricted HF method, and then a full valence Cl treatment. For all alkali pairs, the parallel and perpendicular components of the ground state a at equilibrium distance Rg scale as the cube of Re, which can be related to a simple electrostatic model of an ellipsoidal charge distribution. So, for the ground state, the longitudinal polarizability exhibits a maximum at a distance corresponding to 1.3-1.5 times the equilibrium distance. 

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