摘要 : We propose to describe solution structures by calculating the number of solute molecules containing a certain number of molecules of the same type in their immediate environment. Association in solutions can be studied by consider... 展开 We propose to describe solution structures by calculating the number of solute molecules containing a certain number of molecules of the same type in their immediate environment. Association in solutions can be studied by considering the fraction of these molecules as a function of concentration. We conduct such an analysis using molecular dynamics models of tert-butanol, trimethylamine oxide, and methanol aqueous solutions. Differences between the character of association in these solutions are demonstrated. It is shown that the clustering of dissolved molecules is predominantly universal at low concentrations (<1%) and above the percolation threshold (10%) and is determined by the volume available for the dissolved molecules. Specific interactions between molecules are more pronounced at intermediate concentrations. It is shown that tert-butanol and methanol solutions have similar structures at the concentrations corresponding to the same available volume. 收起