Reaction dynamics minimum dynamic approach

All the calculations were carried out with the Gaussian03 program,37 using the hybrid PBEO functional30,38 and the 6-31+G(d,p) basis set.39 Starting from the transition state, we have calculated reaction pathways for both static and dynamic approaches. On the one hand, we followed the minimum energy path between the transition state and... 

With respect to a more quantitative characterization of the PE function along the reaction coordinate, in terms of local minima and barriers between them, the minimum energy reaction (MER) path concept is more promising. The MER path approach, also called the intrinsic reaction path approach [39], is defined as the steepest descent path from the transition state (a saddle point on the PE surface) down to the local minima that are equilibrium geometries of reactant and product. It has been shown [40] how to express the Hamiltonian of an N atom molecular system in terms of the reaction coordinate, and this approach has been used successfully to describe a variety of processes in polyatomic reaction dynamics. It is also well known that for many reactions (PT process among them) the MER path is very sharply curved, so that the relevant dynamical motion deviates far from it. This is not a particularly important point for our present purpose of a qualitative characterization of the PE surfaces relevant for the PT reaction, as far as we do not consider the dynamics of... 

The import of diabatic electronic states for dynamical treatments of conical intersecting BO potential energy surfaces is well acknowledged. This intersection is characterized by the non-existence of symmetry element determining its location in nuclear space [25]. This problem is absent in the GED approach. Because the symmetries of the cis and trans conformer are irreducible to each other, a regularization method without a correct reaction coordinate does not make sense. The slope at the (conic) intersection is well defined in the GED scheme. Observe, however, that for closed shell structures, the direct coupling of both states is zero. A configuration interaction is necessary to obtain an appropriate description in other words, correlation states such as diradical ones and the full excited BB state in the AA local minimum cannot be left out the scheme. 

From a simulation viewpoint units SO, S6 and S7 may be considered blackboxes. On the contrary, SI to S5 are simulated by rigorous distillation columns, as sieve trays. In the steady state all the reactors can be described by a stoichiometric approach, but kinetic models are useful for Rl, R2 and R4 in dynamic simulation [7, 8]. As shown before, the reaction network should be formulated so as to use a minimum of representative chemical species, but respecting the atomic balance. This approach is necessary because yield reactors can misrepresent the process. 

Dynamic IFT arises from the reaction of acidic components in the crude oil to form petroleum soaps. Reaction of acidic surface-active materials in the crude oil with sodium hydroxide in the aqueous phase is assumed to occur rapidly at the interface, but desorption of these species is taken to be slower. This slower desorption leads to a maximum in the concentration of surface-active species at the interface at some point in time and hence an interfacial tension minimum. Subsequently, IFT increases as equilibrium is approached (58). 

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