Monte Carlo simulations of solutions

In principle, the ideal description of a solution would be a quantum mechanical treatment of the supermolecule consisting of representative numbers of molecules of solute and solvent. In practice this is not presently feasible, even if only a single solute molecule is included. In recent years, however, with the advances in processor technology that have occurred, it has become possible to carry out increasingly detailed molecular dynamics or Monte Carlo simulations of solutions, involving hundreds or perhaps even thousands of solvent molecules. In these, all solute-solvent and solvent-solvent interactions are taken into account, at some level of sophistication. 

John MS (2011) Monte Carlo simulation of solute extraction via supercritical carbon dioxide from polyethylene glycol). Fluid Phase Equilib 305(1) 76—82... 

A final consideration is how parameters from geometrical models might be incorporated into models to better predict solute dispersion at the macroscopic scale. One approach involves the development of effective continuum models for structured soils and fractured rocks (de Josselin de Jong Way, 1972 Long et al., 1982 Berkowitz et al., 1988). Another approach is the inclusion of dispersion due to porosity variations in Monte Carlo simulations of solute transport in random conductivity fields (Fiori, 1998 Hassan et al., 1998). It is also possible to embed geometrical models within multiregion velocity based models (Gwo et al., 1998). 

In principle, simulation teclmiques can be used, and Monte Carlo simulations of the primitive model of electrolyte solutions have appeared since the 1960s. Results for the osmotic coefficients are given for comparison in table A2.4.4 together with results from the MSA, PY and HNC approaches. The primitive model is clearly deficient for values of r. close to the closest distance of approach of the ions. Many years ago, Gurney [H] noted that when two ions are close enough together for their solvation sheaths to overlap, some solvent molecules become freed from ionic attraction and are effectively returned to the bulk [12]. 

Larson R G 1996 Monte Carlo simulations of the phase behavior of surfaotant solutions J. Physique 116 1441... 

R. B. Pandey, A. Milchev, K. Binder. Semidilute and concentrated polymer solutions near attractive walls Dynamic Monte Carlo simulation of density and pressure profiles of a coarse-grained model. Macromolecules 50 1194-1204, 1997. 

A. Milchev, W. Paul, K. Binder. Off-lattice Monte Carlo simulation of dilute and concentrated polymer solutions under theta conditions. J Chem Phys 99 4786-4798, 1993. 

A. Milchev, K. Binder. Osmotic pressure, atomic pressure and the virial equation of state of polymer solutions Monte Carlo simulations of a bead-spring model. Macromol Theory Simul 5 915-929, 1994. 

Fig. 5. Probabilities pn of observing n water-oxygen atoms in spherical cavity volumes v. Results from Monte Carlo simulations of SPC water are shown as symbols. The parabolas are predictions using the flat default model in Eq. (11). The center-to-center exclusion distance d (in nanometers) is noted next to the curves. The solute exclusion volume is defined by the distance d of closest approach of water-oxygen atoms to the center of the sphere. (Hummer et al., 1998a)... 

MONTE CARLO SIMULATIONS OF CHEMICAL REACTIONS IN SOLUTION... 

The combined QM/MM model can be used along with Statistical Perturbation Theory to carry out a Monte Carlo simulation of a chemical reaction in solution, with the advantage of allowing solute electronic structure relaxation in solution. Particularly, the combined AM1/TIP3P force field has recently been applied to simulate several chemical processes in solution. We will refer here briefly to the Claisen rearrangement and to the Menshutkin reaction. 

Connolly R, Timoshenko EG, Kuznetsov YA. Monte Carlo simulations of amphiphihc co-dendrimers in dilute solution. Macromolecules 2004 37 7381-7392. 

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