Examination and Parameterization of Interatomic Potentials for Rare Gas Dimers

4 Examination and Parameterization of Interatomic Potentials for Rare Gas Dimers [77] 

The accuracy of the frozen energy term is also largely influenced by the van der Waals (vdW) term, which is the other part of the frozen density interaction. One of the main challenges with the force field development is to model this vdW interaction. Currently the Lennard-Jones 12-6 term [78], - Bij/Rfj), 

Another commonly used and more physically grounded van der Waals function form is the Buckingham potential [94, 95], as is included with the MM2 and MM3 force fields [96, 97]. It consists of a physically appealing repulsion term, known as the Bom-Mayer exponential function (AR = and an attractive 

Rare gas dimers are prototypical systems to examine van der Waals interaction function forms [88, 92, 98-100]. It should be noted that such examinations on the vdW potentials generally employ the assumption that the total interactions between two rare gas atoms are all from the vdW interactions. A seminal work by Halgren [88] found that neither the Lennard-Jones type potentials (Lennard-Jones 12-6 or Lennard-Jones 9-6) nor the Buckingham exp-6 potentials was able to well replicate the high quality reference data, while a buffered 14-7 potential was found to yield much better performance. It should be noted that in the calculation of van der Waals reference energies by Halgren [88], the charge penetration effects have not been separated out. It is well known that there 

Our results [77] clearly indicate that the reference vdW interaction energies for rare gas dimers can be very well modeled by the sum of a B3LYP-D3 dispersion term and a physically appealing Bom-Mayer exponential function for describing repulsive interactions. 

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