China 
Africa 
Explore chapters and articles related to this topic
Theory of Radiation-Induced Cracking Reactions in Hydrocarbons
Published in Yuriy Zaikin, Raissa Zaikina, Petroleum Radiation Processing, 2013
Cage effect is an important phenomenon that plays a key role in the formation of long-living radical pairs and, therefore, strongly affects the kinetics of low-temperature cracking. Cage effect (or Franck-Rabinowitch effect) is a general name for the phenomenon characteristic of the reactions in liquid and solid phases when pairs of the reacting particles are confined in a small area (cage) surrounded by molecules of the medium (Kochi 1973). A typical cage effect can be observed in the studies of hydrocarbon decomposition.
Molecular simulation study of the glass transition in a soft primitive model for ionic liquids
Published in Molecular Physics, 2019
A. Rodríguez-Rivas, J. M. Romero-Enrique, L. F. Rull
The cage effect affects the molecular dynamics in the low temperature regime, inducing dynamic heterogeneity by the formation of transient spatial regions that exhibit fast and slow dynamics [61]. This implies that the displacement statistics, which is characterised by the van Hove functions, is no longer Gaussian for intermediate times, as it is in the ballistic and diffusive regimes. As we will see, this non-Gaussian character can be characterised by the non-Gaussian parameter defined by Equation (11). Figure 14 shows the behaviour of as a function of the temperature for a given value of . We see that, as expected, this quantity is close to zero for short and long times, showing a maximum for intermediate times. Both the maximum value and the time at which happens increase as temperature decreases. Thus, the time where the maximum of the non-Gaussian parameter occurs defines a relaxation time of the system. The relaxation time and the maximum value of follow approximately a power law of exponent of order 0.3, which is consistent with the values of the b exponent in the von Schweidler law for the β-relaxation regime of the self-intermediate scattering function. We also observe that, for times smaller than this relaxation time, curves corresponding to different temperatures collapse in a master curve. Finally, regarding the dependence on , for a given temperature the non-Gaussian parameter for cations is practically independent of , but it decreases for anions as increases.