Single point charge electrostatic

This field is not the physical electrostatic field observed in the crystal because the ionic model takes no account of the distribution of electrons within the atom. The distributed charge of the atom is replaced by a single point charge at its centre. 

It has been pointed out that the possibility of an atom in a molecule having both positive and negative regions on its surface should be taken into account in designing force fields, e.g., for molecular dynamics [7, 56], These often describe electrostatic interactions in terms of a single point charge associated with each atom. 

If the two charges of the dipole featuring in the layer model are replaced with a single point charge, then the one-layer continuous model relating to electrolyte solutions is obtained. According to this model, the part of the free energy of solvation due to electrostatic interactions is [Ab 78 ]... 

If separate D-RESP charge sets are fitted for every single one of the 36 frames, the standard deviation of the electrostatic field generated varies between 3.5 and 5% with respect to the full quantum reference. This accuracy is the best (in the least-squares sense) that can be obtained if the system is modeled with time-dependent atomic point-charges and represents the accuracy limit for a fluctuating point charge model of the dipeptide. 

The electrostatic potential at any point, V(r), is the energy required to bring a single positive charge from infinity to that point. As each pseudo atom in the refined model consists of the nucleus and the electron density distribution described by the multipole expansion parameters, the electrostatic potential may be calculated by the evaluation of... 

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