Cage effect extending

A very fundamental difference between reactions in condensed matter and isolated molecular processes in the gas phase is the cage effect when a reaction or excitation process occurs in a cluster or in a condensed phase, the surrounding solvent molecules may prevent the separation of the reaction products or excited interacting species or delay such separation, confining the nascent species to the initial cage for an extended period of time. As in the work reviewed in subsection 1.3.2, this involves the interplay of dissociation and energy transfer. There, the emphasis was... 

The ESR studies using amine radicals as a spin probe have been extended to investigate cage effects on stability and molecular dynamics of organic molecules in zeolites [62]. Three zeolites with different cages or channels were employed, i.e.. 

Also, from UT to 58, sponsored by DOD, an extended study on polymerization kinetics was undertaken, particularly of allylic compounds, in cooperation with N. Gaylord, N. Field, H. Starkweather, A. Adicoff and M. Litt, rounding out our knowledge of degradative free radical chain transfer and retarded polymerization. This work led to studies of the mechanism of peroxide decomposition as a function of environments, especially of the cage effect, with W. 

Monchick [36, 273] has used the diffusion equation and radiation boundary conditions [eqns. (122) and (127)] to discuss photodissociative recombination probabilities. His results are similar to those of Collins and Kimball [4] and Noyes [269]. However, Monchick extended the analysis to probe the effect of a time delay in the dissociation of the encounter pair. It was hoped that such an effect would mimic the caging of an encounter pair. Since the cage oscillations have periods < 1 ps, and the diffusion equation is hardly adequate over such times (see Chap. 11, Sect. 2), this is a doubtful improvement. Nor does using the telegraphers equation (Chap. 11, Sect. 3.3) help significantly as it is only valid for times longer than a few picoseconds. 

In small crystals at least, the C o molecules seem to assemble themselves into a somewhat ordered array as if they are effectively spherical, which is entirely consistent with the hypothesis that they are shaped like soccer balls. The excess between the nearest-neighbour distance (10.02 A) and the diameter calculated for the carbon cage itself (7.1 A) must represent the effective van der Waals diameter set by the repulsion of the V electron clouds extending outward from each carbon atom. Because the van der Waals diameter of carbon is usually considered to be 3.3-3.4 A the packing seems a little tighter than one might expect for soccer-ball-shaped C o molecules. The reason for this has not yet been determined. 

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