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901.
In this short review, we provide an update of recent developments in Kramers’ theory of reaction rates. After a brief introduction stressing the importance of this theory initially developed for chemical reactions, we briefly present the main theoretical formalism starting from the generalized Langevin equation and continue by showing the main points of the modern Pollak, Grabert and Hänggi theory. Kramers’ theory is then sketched for quantum and classical surface diffusion. As an illustration the surface diffusion of Na atoms on a Cu(110) surface is discussed showing escape rates, jump distributions and diffusion coefficients as a function of reduced friction. Finally, some very recent applications of turnover theory to different fields such as nanoparticle levitation, microcavity polariton dynamics and simulation of reaction in liquids are presented. We end with several open problems and future challenges faced up by Kramers turnover theory. 相似文献
902.
Enric Sabater Miquel Solà Pedro Salvador Diego M. Andrada 《Journal of computational chemistry》2023,44(3):268-277
The classic pnictogen dichotomy stands for the great contrast between triply bonding very stable N2 molecules and its heavier congeners, which appear as dimers or oligomers. A banner example involves phosphorus as it occurs in nature as P4 instead of P2, given its weak π-bonds or strong σ-bonds. The P2 synthetic value has brought Lewis bases and metal coordination stabilization strategies. Herein, we discuss the unrealized encapsulation alternative using the well-known fullerenes' capability to form endohedral and stabilize otherwise unstable molecules. We chose the most stable fullerene structures from Cn (n = 50, 60, 70, 80) and experimentally relevant from Cn (n = 90 and 100) to computationally study the thermodynamics and the geometrical consequences of encapsulating P2 inside the fullerene cages. Given the size differences between P2 and P4, we show that the fullerenes C70–C100 are suitable cages to side exclude P4 and host only one molecule of P2 with an intact triple bond. The thermodynamic analysis indicates that the process is favorable, overcoming the dimerization energy. Additionally, we have evaluated the host-guest interaction to explain the origins of their stability using energy decomposition analysis. 相似文献
903.
A goodness‐of‐fit test statistic for nonlinear regression models based on local polynomial estimation is proposed in this paper. The criterion used to construct the test is the distance between the parametric fit and the nonparametric regression estimation. The good performance of the test is shown via a simulation study. The method is applied to check a logistic mixture regression model for real data coming from a thermal analysis problem. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献