Pereraa Aurélien, Kezić Bernarda
Faraday Discuss. 2013;167:145-58. doi: 10.1039/c3fd00072a.
The role of concentration fluctuation and micro-heterogeneity in aqueous methanol mixtures are examined by two different methods: computer simulations of two systems with sizes of 2048 and 16 384 molecules, and site-site Ornstein-Zernike integral equation theory with two different closures. The focus is on the short and long range behaviour of the correlation functions, their running integrals and the structure factors. It is found that the micro-heterogeneous nature of these mixtures does not allow a proper stabilisation of the long range tail of the correlations as obtained through computer simulations, even over 6 ns runs. Similarly, approximate closures provide poor estimates of the concentration fluctuations and micro-structure of the mixtures. Interestingly, the analysis of the inadequacies of both these studies provide interesting insights about the nature and interplay of the concentration fluctuations and the micro-heterogeneity in these mixtures.
对包含2048个和16384个分子的两个系统进行计算机模拟，以及采用两种不同封闭近似的位点 - 位点奥恩斯坦 - 泽尔尼克积分方程理论。重点在于相关函数、其累积积分和结构因子的短程和长程行为。研究发现，这些混合物的微观不均匀性质无法使通过计算机模拟得到的相关性长程尾部得到适当稳定，即使在长达6纳秒的模拟运行中也是如此。同样，近似封闭近似对混合物的浓度涨落和微观结构的估计效果不佳。有趣的是，对这两项研究不足之处的分析为这些混合物中浓度涨落和微观不均匀性的性质及相互作用提供了有趣的见解。
