Density functional theory thermodynamic analysis

Thermodynamic Equilibrium, Kinetics, Activation Barriers, and Reaction Mechanisms for Chemical Reactions in Karst Terrains (White, 1997) Solvent Effects On Isomerization Equilibria—an Energetic Analysis in the Framework of Density Functional Theory (Lelj and Adamo, 1995)... 

The parent azine systems discussed in this chapter, compounds 1-4, have not been prepared experimentally, but there has been continuing interest in their theoretical analysis. The past 10 years have seen the incorporation of computational chemistry into the mainstream of chemical research, facilitated by the advancement of computer hardware, and computational software and methods. Hence, not surprisingly, recent studies have been performed using advanced methods, such as MP2, CCSD, and a considerable number of density functional theory (DFT) calculations. Azines have been investigated in terms of structural features, aromaticity, kinetic and thermodynamic stability, and decomposition reactions. 

The applications are so many that it is difficult to select a few. Limiting the attention to some basic issues, one may mention a recent study using density functional theory and molecular orbital G3(MP2) method to provide thermodynamic data for the analysis of the photochemistry of ketones on Ti02. The bond energies of a range of gem-diols, RR C(OH)2, have been used as models for the binding to the titania surface (see Scheme 24). ... 

The relative reaction rates of the 1,3-dipolar cycloaddition reaction of phenyl azide to dipolarophiles containing the C=C bond can be predicted by using the Jaguar V. 3.0 ab initio electronic package. Thermodynamic analysis of the 1,3-dipolar cycloaddition of organic azides with conjugated nitroalkenes at 273-398 K shows that temperature does not affect the course of these reactions in the vapour phase. Density-functional procedures have been used to explain the regioselectivity displayed by the 1,3-dipolar cycloaddition of azides with substituted ethylenes. A density-functional theory study of the 1,3-dipolar cycloaddition of thionitroso compounds with fulminic acid and simple azides indicates that the additions are not stereospeciflc. ... 

One of the biggest problems in the area of mesopore analysis is the hysteresis effect, that is the adsorption isotherm is different from the desorption isotherm. The hysteresis loop formed in the isotherm covers only a portion of the isotherm. The desorption branch of the isotherm always has a higher amount of material adsorbed than does the adsorption branch, which from any semi-thermodynamic point of view makes sense. Several complications have been postulated for the phenomenon. Complicating the subject is a specific case that leads to what appears to be hysteresis, for example partial chemisorption and plastic deformation of the adsorbent. The solution to non-specific hysteresis may be found in density function theory (DFT) calculations of which several have been quite insightful. 

The probability of these processes is a function of the density of states in the conductivity and valence band respectively at the potentials corresponding to the redox potential of the adsorbed species. In the electronic theory of catalysis in the later fifties only general thermodynamic rules were considered, but the conditions of the electron transfer were never applied to analyze the behaviour of different oxide catalysts in the oxidation of hydrocarbons. No quantitative data are available to make such analysis, although recently an attempt was made to interpret the changes of the rate of ethanol oxidation in terms of the density of states (36). The relative positions of the energy bands in the solid and the redox potential of the reacting molecule may be adjusted by a) formation of one or more oxide/oxide interfaces with such values of the contact potentials that the conductivity band will... 

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