Perturbing actions

A distorted conjugated pair of double bonds is an intrinsically chiral chromophoric system, and its overall chiroptical properties depend on the reduced symmetry of the chromophore itself as well as on the perturbing action of a dissymmetric environment. 

One of the most applicable terms in Van t Hoff s studies was the perturbation actions. In Van t Hoff s opinion, "normal transformations take place very rarely... . Reaction rate is subjected to various effects to such an extent that the investigation of the transformation process reduces mainly to that of perturbation effects. Van t Hoff did not concentrate on "perturbation effects as inhomogeneity, non-isothermality, and the occurrence of some secondary reaction. To his mind, the main thing that merits special consideration is the effect of the medium on the reaction rate ("primarily the effect of the media of obviously chemical nature ). 

This solution is only approximate as the electron is also attracted towards the nucleus which thus exerts upon the electron a perturbing action. The term perturbation has been borrowed from planetary mechanics. If it be imagined that the movement of the earth round the sun has been calculated considering only the presence of those two bodies, then this calculation would only be approximate since other planets, e.g. Mars, exert some influence on the path followed by the earth. This influence is termed perturbation and the resultant orbit is a perturbed orbit. 

The dynamic interaction between flow and drops and bubbles floating in the flow may deform or even destroy them. This phenomenon is important for chemical technological processes since it may change the interfacial area and the relative velocity of phases and cause transient effects. In this case, the viscous and inertial forces are perturbing actions, and the capillary forces are obstructing actions. The bubble shape depends on the Reynolds number Re = aeU,p/p and the Weber number We = aeU2p/cr, where p, and p are the dynamic viscosity and the density of the continuous phase, a is the surface tension coefficient, and ae is the radius of the sphere volume-equivalent to the bubble. 

In a hydrocarbon medium, the formation of a triplet intermediate is not possible since AE < 0 because of the perturbing action of the counterion. The value of f increases with temperature and the content of the vinyl structure also increases. This change is not so marked as in the case of the electron donor presence because in the hydrocarbon medium, AE depends slightly on temperature. 

According to this argument it would appear that the molecules which can most effectively communicate vibrational energy to miother are those which exert the maximum perturbing action on its potential energy curve. This idea is in a general way borne out by experiment. 

The following calculation, though crude, is significant, and illustrates a typical effect. Suppose that n solvent molecules suitably grouped around a transition complex lower the value of E by their united perturbing actions. Each makes a contribution e to the lowering so that AE = Tie. Let the chance that any one of them is correctly disposed for the job bep then the overall chance of their co-operation is p , where p is less than unity. Compared with reaction in absence of solvent the rate now rises in the ratio and falls in the ratio p . In the equation k = we have AE = ne, P/Pq = p, ... 

Therefore, it may be concluded that all the water confined in narrow mesopores of Si-60 is subjected to the perturbing action of the surface. The data given in Figure 4.30 make it possible to arrive at a conclusion that the hydrophilicity of the surface is minimal for AC-1 as a result of carbonization. It increases for CS samples prepared using metal acetylacetonates in comparison with AC-1 but it remains lower than that of Si-60. The amounts of WBW are minimal for Si-60. 

The perturbing action of the surface cannot be accounted for by comparison with the phase diagrams for filled and unfilled alloys. For comparison of the phase diagrams and data on AB, we have to use the unperturbed%ab values. The comparison of data calculated by two methods allows estimation of the contribution to the system stability both of the changes in the perturbed component interaction and in the decreasing stability of each component in the filled system. The calculation by the first method gives only changes in the interphase interaction between two polymers, whereas the second method represents the total effect of filler action on the thermodynamic stability of the system. 

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