Electrostatic damping

EFP parameters for water and benzene were obtained with the 6-311++G(3df,2p) basis set. The benzene EFP is the same as that discussed above. Electrostatic parameters for water were obtained with a numerical DMA, and electrostatic interactions were screened by the high-order electrostatic damping functions. Additionally, for both benzene and water, polarization interactions were screened as well, with damping parameters at all centers being set to 1.5. 

Electrostatic capacitances help to tame and damp the arriving surge... 

The CH---7T bond is effective in water. The CH-tt interaction depends mostly on dispersion forces and hence, unlike electrostatic interactions, it is not damped by polar solvents. As a result the interaction is a significant contributor to the hydrophobic effect. 

However, the value returned will not have units of kJ mol-1 and a multiplier of 1390.0 must be applied (see Appendix 2). If e is taken to be 4 then we calculate an energy of 4.63 kJ mol-1, and if s is taken to be 4d then this becomes 1.54 kJ mol1. The greater the value of e the smaller the electrostatic energy that is calculated -because the higher the dielectric constant, the more the electrostatic interaction is damped. Shown in Fig. 17.9.3 are curves for electrostatic interactions between these atoms for e = 4 and for e = 4 d. 

The joining of the two parts is made by damping the electrostatic potential with an ad hoc damping function d R), which proved its usefulness in many other instances see Toennies et al. [80]. 

In the EH-CSD approach it is not convenient to decouple electrostatic terms into rigid Coulombic and polarization contributions the effective Hamiltonian leads to compute these two terms together. Exchange repulsive terms are hardly computed when the second partner of the interaction is a liquid they may be obtained with delicate simulation procedures, and it is convenient to decouple them into two contributions, namely the work spent to form a cavity of a suitable shape and an additional repulsion contribution. Dispersion contributions may be kept we shall examine this term in more detail later. Charge-transfer contributions are damped in liquids their inclusion could introduce additional problems in the definition of Vjnt via continuous solvent distributions. It is advisable to neglect them, as it is done in the interaction potentials used in simulations with the present approach it is possible to describe the charge transfer effect by enlarging the solute M —> M-Sn. 

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