物理化学学报 >> 1986, Vol. 2 >> Issue (05): 437-443.doi: 10.3866/PKU.WHXB19860508

研究论文 上一篇    下一篇

扩散不稳定相中的化学稳定性和时-空有序结构的形成

李如生   

  1. 清华大学化学系, 北京
  • 收稿日期:1985-01-17 修回日期:1986-03-26 发布日期:1986-10-15
  • 通讯作者: 李如生

THE CHEMICAL STABILITY AND THE FORMATION OF SPATIO-TEMPORAL ORDERED STRUCTURES

Li Rusheng   

  1. Department of Chemistry; Tsinghua University; Beijing
  • Received:1985-01-17 Revised:1986-03-26 Published:1986-10-15
  • Contact: Li Rusheng

摘要: 利用热力学和动力学的分析方法, 研究了化学稳定性和扩散稳定性的依赖关系。发现, 在远离平衡和强烈非理想的体系中, 不管体系是否扩散稳定, 化学反应可以是稳定的, 也可以是不稳定的。通过对Schlögl模型的分析, 表明扩散不稳定性和化学稳定性之间的竞争可以导致一类时空有序结构的形成。这一结果可以看作是耗散结构理论的推广和延伸。

Abstract: Based on the thermodynamic and kinetic analyses of Schlogl model in nonideal condition, the dependent relation between chemical stability and diffusion stability is studied. It is found that, under the conditions that the system is far from chemical equilibrium and is strongly nonideal, both excess entropy δ~2S and its time-derivative for some space-uniform steady state may, independently to a certain extent, be positive or negative. Thus the chemical reactions and diffusion may show same or different stabilities in both cases that diffusion is stable and unstable. The linear stability analysis of kinetic equation for Schlögl model has confirmed this Clansdorff-Prigogine theory of nonequilibrium thermodynamic stability which concerns itself mainly about the chemical stability in diffusionstable systems.
When system is diffusion-unstable but chemically stable, their competition might give rise to the formation of some ordered structures (dissipative structures), as it does when system is diffusion-stable but chemically unstable. The numerical simulations have confirmed this prediction. Since the phenomena of diffusion instability are rather common in practical systems, such consideration of formation of ordered structures through the competition between chemical stability and diffusion instability may expand the applications of the theory of dissipative structures.