Polarizable water model

A related, relatively unexplored topic is the importance of many-body forces in the simulations of interfacial systems. The development of water-polarizable models has reached some level of maturity, but one needs to explore how these models must be modified to take into account the interactions with the metal surface atoms and the polarizable nature of the metal itself... 

Piquemal J-P, Chelli R, Procacci P, Gresh N (2007) Key role of the polarization anisotropy of water in modeling classical polarizable force fields. J Phys Chem A 111 8170... 

Lamoureux G, MacKerell AD, Roux B (2003) A simple polarizable model of water based on classical Drude oscillators. J Chem Phys 119(10) 5185—5197... 

Lamoureux G, Harder E, Vorobyov IV, Roux B, MacKerell AD (2006) A polarizable model of water for molecular dynamics simulations of biomolecules. Chem Phys Lett 418(l-3) 245-249... 

Yu HB, Hansson T, van Gunsteren WF (2003) Development of a simple, self-consistent polarizable model for liquid water. J Chem Phys 118(1) 221—234... 

Yu HB, Geerke DP, Liu HY, van Gunsteren WE (2006) Molecular dynamics simulations of liquid methanol and methanol-water mixtures with polarizable models. J Comput Chem 27(13) 1494-1504... 

Sprik M, Klein ML (1988) A polarizable model for water using distributed charge sites. J Chem Phys 89(12) 7556-7560... 

Chelli R, Barducci A, Bellucci L, Schettino V, Procacci P (2005) Behavior of polarizable models in presence of strong electric fields. I. Origin of nonlinear effects in water point-charge systems. J Chem Phys 123(19) 194109... 

Chialvo AA, Cummings PT (1996) Engineering a simple polarizable model for the molecular simulation of water applicable over wide ranges of state conditions. J Chem Phys 105(18) ... 

Mahoney MW, Jorgensen WL (2001) Rapid estimation of electronic degrees of freedom in Monte Carlo calculations for polarizable models of liquid water. J Chem Phys 114(21) 9337-9349... 

In general, however, the majority of properties do not yet seem to be more accurately predicted by polarizable models than by unpolarizable ones, provided adequate care is taken in the parameterization process. Of course, if one wishes to examine issues associated with polarization, it must necessarily be included in the model. In the area of solvents, for instance, Bernardo et al. (1994) and Zhu and Wong (1994) have carefully studied the properties of polarizable water models. In addition, Gao, Habibollazadeh, and Shao (1995) have developed... 

Paricaud, P., Predota M., Chialvo A.A. and Cummings P.T., From dimer to condensed phases at extreme conditions Accurate predictions of the properties of water by a Gaussian charge polarizable model. J. Chem. Phys. (2005) 122 244511. 

Recent sequential molecular dynamics/quantum mechanics (MD/QM) calculations of the water dipole moment [51] using a polarizable model for water [52] indicate that the average dipole moment in the liquid is not dependent on the number... 

A large number of polarizable models have been developed for water, many of them with one polarizable site (with a = 1.44 A ) on or near the oxygen position. For these models, the polarizable sites do not typically get close enough for polarization catastrophes (4aa) = 1.4 A, see comments after Eq. [16], so screening is not as necessary as it would be if polarization sites were on all atoms. However, some water models with a single polarizable site do screen the dipole field tensor. Another model for water places polarizable sites on bonds. Other polarizable models have been used for monatomic ions and used no screening of T or gO 15,16,27,34 Polarizable models have been developed for proteins as well, by Warshel and co-workers (with screening of T but not and by Wodak and... 

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-... 

For gas-phase properties, the second virial coefficient, B(T), provides one of the most sensitive tests of a water model.Both polarizable and non-polarizable models are capable of reproducing experimental values of B T), and some models have even been parameterized to do so explicitly. Polarizable models appear to provide significant improvements in reproducing not only the second virial coefficient, " but also the third coefficient. 

In the liquid phase, calculations of the pair correlation functions, dielectric constant, and diffusion constant have generated the most attention. There exist nonpolarizable and polarizable models that can reproduce each quantity individually it is considerably more difficult to reproduce all quantities (together with the pressure and energy) simultaneously. In general, polarizable models have no distinct advantage in reproducing the structural and energetic properties of liquid water, but they allow for better treatment of dynamic properties. 

It is now well understood that the static dielectric constant of liquid water is highly correlated with the mean dipole moment in the liquid, and that a dipole moment near 2.6 D is necessary to reproduce water s dielectric constant of s = 78 T5,i85,i96 holds for both polarizable and nonpolarizable models. Polarizable models, however, do a better job of modeling the frequency-dependent dielectric constant than do nonpolarizable models. Certain features of the dielectric spectrum are inaccessible to nonpolarizable models, including a peak that depends on translation-induced polarization response, and an optical dielectric constant that differs from unity. The dipole moment of 2.6 D should be considered as an optimal value for typical (i.e.. 

Simple Polarizable Model for the Molecular Simulation of Water Applicable over Wide Ranges of State Conditions. 

Estimation of Electronic Degrees of Freedom in Monte Carlo Calculations for Polarizable Models of Liquid Water. 

It is also clear that the main limit of the models discussed so far is the lack of the most important many-body effect of water, i.e. polarizability. Several three- [86,94, 98,100,108], four- [45,100,105,106,109,110], five- [75,107], six- [109,110] and seven-site [67,92,94,98,102] polarizable models have been introduced in the last decade. Among the simplest empirical models we mention POL, POLl and the recent semi-empirical POL2, see Table 3. 

The drive behind the development of polarizable models for water is also due to the important role polarizability is expected to play in aqueous solvation of ions and polar molecules. It has long been debated in the literature if explicit treatment of polarizability in a model is to be preferred to the use of effective potentials including non-additivity in an average way [12,94,98,114,115,118-121,187,188]. 

Larger differences between polarizable and effective models are to be expected, as suggested by Jorgensen et al [188], when dealing with solutions of di- and trivalent ions. A study of the effect of water polarizability on thermodynamic stability and kinetic lability of hydration complexes of a few lanthanide ions (Nd ", Sm, Yb " ) has been carried out by Kowall et al [189]. 

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