温度对二甲基亚砜水溶液的结构和热力学性质的影响

Effect of Temperature on the Structural and Thermodynamic Properties of Aqueous Dimethyl Sulfoxide

应用参考作用格位模型理论计算了二甲基亚砜(DMSO)摩尔分数为0.002时不同温度下溶液的微观结构和热力学性质.计算结果表明,DMSO加入到水中能够增强溶液的分子网络结构.温度升高,配位数减小,溶液中分子排布趋向无序.平均力势的波动增大表明分子间的诱导力表现为斥力.计算得到的各种热力学性质显示:温度升高,溶液的熵和溶剂化自由能增加,相互作用能和过剩化学位也增加,即高温下溶液越来越偏离理想溶液;空位形成能降低表明溶液分子结构在高温下更容易重组.

The structural and thermodynamic properties of aqueous dimethyl sulfoxide（DMSO） at a mole fraction of 0.002 were investigated using referenced interaction site model theory at different temperatures.The results reveal that the water network structure is enhanced by the presence of DMSO.The increased fluctuation in the potential of mean force suggests that the water-induced force is repulsive.In addition,the increased entropy of solvation and free energy of solvation imply that the randomness of the solution increases with an increase in temperature.The increased interaction energy and excess chemical potential reveal that the solution deviates from an ideal solution.Furthermore,the increased cavity reorganization energy shows that the system structure reorganizes easily at high temperature.