Reaction force theoretical calculations

Discrepancies between experimentally obtained and theoretically calculated data for cadmium concentration in the strip phase are 10-150 times at feed or strip flow rate variations. These differences between the experimental and simulated data have the following explanation. According to the model, mass transfer of cadmium from the feed through the carrier to the strip solutions is dependent on the diffusion resistances boundary layer resistances on the feed and strip sides, resistances of the free carrier and cadmium-carrier complex through the carrier solution boundary layers, including those in the pores of the membrane, and resistances due to interfacial reactions at the feed- and strip-side interfaces. In the model equations we took into consideration only mass-transfer relations, motivated by internal driving force (forward... 

Theoretical calculations have shown that the driving force for the overall reaction is the formation of the very stable Si-Cl bond. New systems to convert critical halogen-containing organic compounds into more innocent compounds based on this reaction can be envisaged. 

In 2001, van Duin (Van Duin et al, 2001) proposed a technique of reaction force field, this method was applied to carbohydrates, the geometry data of compounds from simulation are consistent with the literature well, and the bond parameters agree to the results of quantum chemistry, but the calculation time is much less than the time required for quantum chemical calculations. Subsequently, researchers come to realize the advantages of the reaction force field method compared with quantum chemistry and electrostatic force field methods. Reaction force field parameters that are suitable for other materials have gradually been developed, such as silicon oxide, platinum, and titanium. The reaction force field parameters are theoretically universal and general. When Kim et al (2013) studied the interaction between the titanium oxide and water, sodium ions, chloride ions, methanol, and formic acid and other substances, the interaction parameter of Cl/O/H and Na/O/H is from the hteratures of different systems. 

Classical simulations often lack the crucial insight into the problem, because one cannot simply use the force to characterize all the possible interactions. Fortunately, with decades of development, theoretical calculations have become quite sophisticated for crystals and molecules, although not yet for realistic nanometer-sized materials. For solids, the pseudopotential as well as the full-potential linearized augmented plane-wave (FLAPW) method within the density functional theory are well developed. Modern quantum chemical techniques (Gaussian98 [5] and MOLPRO [6]) are quite efficient to compute the potential surfaces for a given molecule. In order to illustrate those possibilities, we show some of our own results in simulating the reaction path for a segment of the retinal molecule in rhodopsin [7]. 

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