Sticky spheres and related systems
Sticky spheres and related systems
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粘球及相关系统
DOI：
10.1007/bf01030007
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发表时间：
1991
影响因子：
1.6
通讯作者：
G. Stell
中科院分区：
文献类型：
--
作者：
G. Stell
本文讨论了具有吸引力的威尔斯阱的硬核粒子系统在巴克斯特粘性球极限和相关极限下的一些性质，以及接近这些极限的方法。Stell和威廉姆斯的结果，即粘性球的直径相等的巴克斯特限制是不稳定的演示给出，并在其中的大小多分散性可以预期恢复热力学稳定性的方式进行了讨论。这些结果的影响PY粘性球近似和最近的粘性球的计算机模拟，然后检查。它的结论是巴克斯特PY粘性球近似的单分散系统可能是一个合理的一个稍微多分散系统的粘性球，现有的模拟结果也可能是相关的这样一个系统。然而，为了使PY近似有用，一个系统必须在定量方面如何多分散还有待观察。的问题是否PY粘性球近似可能被证明是有用的和适当的描述单分散系统与对潜在的吸引力威尔斯aren't非常狭窄的也被认为是值得注意的，它是关于这个问题的有力证据似乎也缺乏。系统附近的影响，但不是在，零吸引阱宽度的限制也被认为是，特别是在相对大小的阱宽度和排斥核的大小多分散性的程度方面。这种考虑胶体系统的可能的相关性进行了观察。考虑到非常长的平衡时间，可以预期的系统非常狭窄的吸引力威尔斯的重要性也指出，在连接与真实的胶体系统和计算机模拟。进一步观察到，在巴克斯特限制粘性球描述的量子力学是难以区分的硬球，所以描述的零阱宽极限附近，量子行为取决于束缚态的数量，从而阱深度以及相对大小的德布罗意布罗意热波长和阱宽。引用了与上述问题相关的相关结果和调查。
Some properties of a system of hard-core particles with attractive wells in the Baxter sticky-sphere limit and a related limit are considered, as is the approach to these limits. A demonstration of the result of Stell and Williams that sticky spheres of equal diameter in the Baxter limit are not thermodynamically stable is given, and the way in which size polydispersity can be expected to restore thermodynamic stability is discussed. The implications of these results for the PY sticky-sphere approximation and recent sticky-sphere computer simulations are then examined. It is concluded that the Baxter PY sticky-sphere approximation for a monodisperse system may well be a reasonable one for a slightly polydisperse system of sticky spheres and that existing simulation results may also be relevant to such a system. How polydisperse a system must be in quantitative terms in order for the PY approximation to be useful remains to be seen, however. The question of whether the PY sticky-sphere approximation may prove to be useful and appropriate in describing monodisperse systems with pair potentials for which the attractive wells arenot extremely narrow is also considered; it is noted that firm evidence concerning this question also appears to be lacking. Implications for systems near, but not in, the limit of zero attractive-well width are also considered, especially in terms of the relative size of the well width and the degree of size polydispersity in the repulsive cores. The possible pertinence of such considerations to colloidal systems is observed. The importance of taking into consideration the extremely long equilibration times that can be expected for systems with very narrow attractive wells is also pointed out, in connection both with real colloidal systems and in computer simulations. It is further observed that in the Baxter limit sticky spheres described quantum mechanically are indistinguishable from hard spheres so described; near the zero-well-width limit, the quantal behavior hinges on the number of bound states and thus the well depth as well as the relative size of the de Broglie thermal wavelength and the well width. Related results and investigations relevant to the issues described above are cited.