Conductor-like models

From a chemical perspective, dielectric- and conductor-like continuum models give sufficiently similar electrostatic results that the differences in their underlying assumptions appear to have no impact. Conductor-like models seem to be slightly more computationally robust in some instances, which may make tliem a better choice if instability is manifest in an SCRF calculation. Some concerns were raised initially that the post facto correction for dielectric behavior might render the models appropriate only for media having reasonably high dielectric constants, but a systematic study by Dolney et al. (2000) indicated non-polar solvents to be equally amenable to treatment by a COSMO model. 

Free Energy Functional for the Conductor-like Model... 

In the case of the conductor-like model a free energy functional that meets the requirements set forth in the Introduction is readily available. Indeed, in the limit of a conductor, the potential must vanish inside and at the boundary of the medium. Thus the functional can be written in the form ... 

Although quite obvious, it is important to remark that a perfect conductor-like model completely neglects the chemical nature of the metal (i.e., all the metals behave in the same way). This is different to what happens for solvents, where even the simplest models include at least one solvent-specific parameter, the static dielectric constant. However, the chemical nature of the metal is relevant for another aspect of the static dielectric response that is neglected by the conductor model the nonlocal effects. They will be discussed in the following Section, The Response Properties of a Molecule Close to a Metal Specimen Surface Enhanced Phenomena and Related Continuum Models. 

For the free energy of solvation calculation, however, it is difficult to discern the most accurate method. Recently, there have been numerous publications exploring the use of the cluster continuum method with anions. With regard to implicit solvation, there are no definite conclusions to the most accurate method, yet for the PB models the conductor-like models (COSMO CPCM) appear to be the most robust over the widest range of circumstances [23]. At this writing, the SMVLE method seems to be the most versatile, as it can be used by itself, or with the implicit-explicit model, and the error bars for bare and clustered ions are the smallest of any continuum solvation method. The ability to add explicit water molecules to anions and then use the implicit method (making it an implicit-explicit model) improves the results more often than the other implicit methods that have been used in the literature to date. 

PCM are explicated in Table 11.1. Also listed in this table are the forms of K and R for the so-called conductor-like model, C-PCM [25]. This model is considerably simpler in that the matrix D is absent. C-PCM is identical to the generalized conductor-iike screening modei (GCOSMO) [78], and almost identical to the original COSMO [37]. (G]COSMO was introduced prior to SS(V)PE/1EF-PCM, based on ad hoc arguments and designed to achieve the correct oo limit. We... 

Klamt A 1995. Conductor-like Screening Model for Real Solvent A New Approach to the Quantitativt Calculation of Solvation Phenomena. Journal of Physical Chemistry 99 2224-2235. 

The conductor-like screening model (COSMO) is a continuum method designed to be fast and robust. This method uses a simpler, more approximate equation for the electrostatic interaction between the solvent and solute. Line the SMx methods, it is based on a solvent accessible surface. Because of this, COSMO calculations require less CPU time than PCM calculations and are less likely to fail to converge. COSMO can be used with a variety of semiempirical, ah initio, and DFT methods. There is also some loss of accuracy as a result of this approximation. 

COSMO (conductor-like screening model) a method for including solvation effects in orbital-based calculations... 

The Polarizable Continuum Model (PCM) employs a van der Waals surface type cavity, a detailed description of the electrostatic potential, and parameterizes the cavity/ dispersion contributions based on the surface area. The COnductor-like Screening... 

COSMO-RS conductor-like screening model for realistic solvation... 

In 1995, one of the authors (A.K.) introduced the state of a molecule embedded in a perfect conductor as an alternative reference state, which is almost as clean and simple as the vacuum state. In this state the conductor screens all long-range Coulomb interactions by polarization charges on the molecular interaction surface. Thus, we have a different reference state of noninteracting molecules. This state may be considered as the North Pole of our globe. Due to its computational accessibility by quantum chemical calculations combined with the conductor-like screening model (COSMO) [21] we will denote this as the COSMO state. 

Klamt, A. Conductor-like screening model for real solvents a new approach to the quantitative calculation of solvation phenomena. J. Phys. Chem. 1995, 99, 2224-2235. 

D. M. Dolney, G. D. Hawkins, P. Winget, D. A. Liotard, C. J. Cramer, and D. G. Truhlar, A universal solvation model based on the conductor-like screening model, J. Comput. Chem. 21 340 (2000). 

E-B. A model solution to the electrostatic problem, e.g., the Generalized Bom Approximation or a conductor-like screening solution. 

In addition to these external electric or magnetic field as a perturbation parameter, solvents can be another option. Solvents having different dielectric constants would mimic different field strengths. In the recent past, several solvent models have been used to understand the reactivity of chemical species [55,56]. The well-acclaimed review article on solvent effects can be exploited in this regard [57]. Different solvent models such as conductor-like screening model (COSMO), polarizable continuum model (PCM), effective fragment potential (EFP) model with mostly water as a solvent have been used in the above studies. 

Conductor-like screening model (COSMO) is one of variants of PCM method [29]. In this method, the cavity is considered to be embedded in a conductor with an infinite dielectric constant [29]. An extension to this method, called COSMO-RS... 

Conductor-like screening model for real solvenfs COSMO-RS... 

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