COSMO methodology

Combining the PCM approach with the gas phase methodology is the most promising way to understand and model the effect of a water solution. The COSMO model was used for the determination of the interaction energies and the activation barriers at the CCSD(T)/6-31++G(d,p) level. 

For the benefit of those readers who are familiar with the paradigms of modern science, but find the arguments and methodologies of cosmology totally bewildering, it is necessary to provide a historical survey of how two pursuits, so disparate, could develop from their common root of astronomy. Naked-eye astronomy never was powerful enough to establish a definitive model of the cosmos and to eliminate fanciful notions based on personal conviction or dogmatic prescription. 

This methodology inspired the chapter on world geometry, based on the assumption that the cosmos is best described by the most consistent version of geometry available at the time. It enables the study of subtleties that cannot be revealed by a more primitive version and anticipates better comprehension of the world through geometries of the future. In the same spirit the present chapter explores the theories of physics and the cosmic picture that they reveal. The next chapter will examine chemical theory in the same way. 

Several groups have also made relevant contribution to the evolution of the original PCM. A related model based on conductor-like screening (COSMO) has been developed recently by Klamt and Schuiirmann [13]. Likewise, another approach to the PCM has been proposed in which the cavity surface is determined in terms of an electronic isodensity surface [14]. Olivares del Valle and coworkers [15] have focused their attention on aspects such as the inclusion of correlation effects in the PCM, or on the role of nonadditive effects in solute-solvent interactions. Pascual-Ahuir et al. [16] have paid most attention to the problem of the definition of the cavity surface. The work done in Barcelona has focussed mainly on the parametrization of the PCM to treating aqueous and nonaqueous solvents, as well as the application of the PCM to the study of biochemical systems [17, 18]. Finally, we and others have made new methodological developments to allow the implementation of the PCM in molecular dynamics or in Monte Carlo calculations [19]. 

COSMO-RS is a fluid phase thermodynamics method for property prediction of the liquid phase that was first introduced in 1995 by A. Klamt [7]. A concise review of the methodology was published in 2011 [8], and a detailed introduction can be found in Ref. [9], thus only a short summary of the most important aspects of the approach will be given here. 

Several methods have been applied to calculate the void volume of RTILs (the fractional free volume, EFV), outstanding among these is the application of the COSMO-RS methodology by Palomar et al. and Shannon et al. [47, 298]. For 23 imidazolium RTILs (Cimim to Cgmim) with a variety of anions a negative bias of — 1.6 % was found [47] between the COSMO-RS-calculated densities and the experimental ones, and a standard deviation of 2.6 % also resulted. 

Wetting of the surface is simulated by means of the COSMO method. The detailed methodology using the COSMO approach is given in a previous publication, but we give a brief overview of the SAS and the calculation of the solvation energy. 

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