Computer simulation charge transfer calculations

Following the early studies on the pure interface, chemical and electrochemical processes at the interface between two immiscible liquids have been studied using the molecular dynamics method. The most important processes for electrochemical research involve charge transfer reactions. Molecular dynamics computer simulations have been used to study the rate and the mechanism of ion transfer across the water/1,2-dichloroethane interface and of ion transfer across a simple model of a liquid/liquid interface, where a direct comparison of the rate with the prediction of simple diffusion models has been made. ° ° Charge transfer of several types has also been studied, including the calculations of free energy curves for electron transfer reactions at a model liquid/liquid... 

Figure 60. Comet-tail CO+(A1l —>X2 2+) spectra from (a, c) luminescent ion-molecule reaction C++02- C0+ + 0 at lab = 5 eV (b,d), charge-transfer reaction Ar+ +CO->CO+ + Ar at lab=1000 eV. Experimental spectra (a, b) were obtained with 2-nm spectral resolution. Tabulated band heads for CO+ (A— BX) system are indicated. Spectral lines designated as Ar(II) and C(I) do not belong to CO+ emission. Dashed portion of curves was not actually measured. Spectra simulated by computer calculations are given in diagrams (c and d). Rotational distributions assumed in simulation calculations were thermal with T= 45,000°K (c) and 1000°K (

Speedy and accurate desktop computers and modern programs such as HYPERCHEM place quantum mechanical calculations within the reach of any experimental chemist. The CURES-EC procedure simulates equilibrium methods of measuring electron affinities by calculating the difference between the optimized forms of the anion and neutral. The READS-TCT determination of charge densities in anion complexes simulates thermal charge transfer experiments. The effect of... 

Our interest in the photooxidation of Fe " in aqueous solution derives from our more general interest in the effects of solvents on electronic transitions, particularly those in which strong specific interactions with solvent molecules are present (42,45,46). We proceed by performing electronic structure calculations, hquid structure simulations, and spectroscopic calculations for mechanisms 1, 3, and 4, investigating the nature of the photochemical processes of aqueous Fe. In particular, we first require the gas-phase absorption frequencies and intensities of the Fe (H20)6 complex, using both ab initio and semi-empirical (INDO-MRSCI) techniques. Second, we need to determine the structure of water around the Fe " ion in solution. Third, we need to determine the solvent shifts of the absorption bands to evaluate transition energies in solution. This will lead to an estimation of relative importance of all but the charge transfer to solvent process (mechanism 2), calculation of which is beyond die capacity of our present computational facihties. The potential surfaces em-... 

The papers presented in the conference span the spectrum of activity in the science of alloys. The theoretical presentations ranged in content from fundamental studies of electronic structure, to first-principles calculations of phase diagrams, to the effects of charge transfer, to the temperature dependence of short-range order parameters. They encompassed the study of mechanical properties, the properties of dislocations, of phase evolution, and computer simulations. Experimental studies were presented based on a variety of state of the art experimental techniques, from TEM to synchrotron diffraction. The phenomena studied varied from the precipitation of nitrides in steel, to the wetting of interfaces between two different crystal structures, to the ordering of vacancies in carbides. And the materials whose properties were measured ranged from Transition metals, to the Lanthanides, to the Actinide series of compounds and alloys. 

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