Polarizable simple point charge

Zhu SB, Yao S, Zhu JB, Singh S, Robinson GW (1991) A flexible polarizable simple point-charge water model. J Phys Chem 95(16) 6211—6217... 

Flexible/Polarizable Simple Point Charge Water Model. 

More realistic treatment of the electrostatic interactions of the solvent can be made. The dipolar hard-sphere model is a simple representation of the polar nature of the solvent and has been adopted in studies of bulk electrolyte and electrolyte interfaces [35-39], Recently, it was found that this model gives rise to phase behavior that does not exist in experiments [40,41] and that the Stockmeyer potential [41,42] with soft cores should be better to avoid artifacts. Representation of higher-order multipoles are given in several popular models of water, namely, the simple point charge (SPC) model [43] and its extension (SPC/E) [44], the transferable interaction potential (T1PS)[45], and other central force models [46-48], Models have also been proposed to treat the polarizability of water [49],... 

Most nonpolarizable water models are actually fragile in this regard they are not transferable to temperatures or densities far from where they were parameterized. Because of the emphasis on transferability, polarizable models are typically held to a higher standard and are expected to reproduce monomer and dimer properties for which nonpolarizable liquid-state models are known to fail. Consequently, several of the early attempts at polarizable models were in fact less successful at ambient conditions than the benchmark nonpolarizable models, (simple point charge) and TIP4P (transfer-... 

This is obviously not the case if the solvent electronic polarizability is treated explicitly (as discussed earlier) because it will respond differently to the different charge distributions in the two electronic states. If one uses the simple point charge model for the solute and solvent molecules, then the dependence of the... 

To identify the polarizability of the sphere, it is left to compare this solution to the solution of the electric field in the presence of a point dipole. To solve this problem, the simple model of a point dipole displayed in Figure 4.6 is used. Here two opposite point charges are separated by a distance / about the origin. The charge distribution is then... 

In the water trimer induction nonadditivity provides a dominant contribution, which effectively overshadows all the other terms. Its mechanism is simple. For instance, in a cyclic water trimer the multipoles of A inductively alter the multipoles at B, which, in turn, inductively alter the multipoles at C, which then alter those on A, and so on, until the self-consistency is reached. Various formulations of this simple model were implemented in the simulations since the 1970s [84-87,63,64,50]. To include the many-body induction effects of point charges interacting with a set of polarizable atomic centers the following classical electrostatics equation is solved iteratively... 

We developed expressions for EOM-CCSD-PCM in the SS formalism, and a series of approximations to reduce the considerable computational cost of this approach. Christiansen and Mikkelsen originally developed the LR formalism for the CCSD wave function in solution for a simple continuum solvation model. Later, they extended it to their flavour of explicit polarizable solvation model. Cammi has also presented several interesting developments in this research area, including a rederivation of the LR-CCSD expressions for PCM, and we presented the first implementation of the method. Other examples of CC methods combined with (non-)polarizable solvation models [e.g., fixed point charges) are also available in the literature. ... 

In the Polarizable Continuum Model for solvation, the molecular solute is hosted in a cavity of a polarizable dielectric medium representing the solvent The cavity is accurately modeled on the shape of the molecular solute (Miertus et al. 1981), and the dielectric medium is characterized by the dielectric permittivity e of the bulk solvent The physics of the model is very simple. The solute charge distribution polarizes the dielectric medium, which in turn acts back on the solute, in a process of mutual polarization that continues until self-consistence is reached. The polarization of the solvent is represented by an apparent charge distribution (ASC) spread on the cavity surface. In computational practice the ASC is discretized to a set of NTS point charges and the solute-solvent interaction is expressed as in terms of the interaction between these and the charge distribution of the molecular solute. 

To give a simple classical model for frequency-dependent polarizabilities, let me return to Figure 17.1 and now consider the positive charge as a point nucleus and the negative sphere as an electron cloud. In the static case, the restoring force on the displaced nucleus is d)/ AtteQO ) which corresponds to a simple harmonic oscillator with force constant... 

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