Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, USA.
J Phys Chem B. 2010 Apr 1;114(12):4261-70. doi: 10.1021/jp9101477.
Gibbs ensemble Monte Carlo simulations are employed to examine the influence of moderately strong electric fields on the vapor-liquid coexistence curves and on structural and energetic properties of the saturated phases of water, methanol, and dimethyl ether. The application of an electric field of 0.1 V/A increases the critical temperature and normal boiling point by approximately 3% compared to the zero field case for all three compounds, whereas the critical density is found to decrease by 1% for methanol and dimethly ether and by 3% for water. For the special case of an electric field applied in only the liquid phase, these effects are magnified with a 4% increase in T(C) and a 13% decrease in rho(C). For the case of an electric field in only the vapor phase, the opposite effect is seen with a 4% decrease in T(C) and a 12% increase in rho(C). Structural analysis shows very little change in the radial distribution functions, but greatly increased orientational ordering with the application of an electric field. The orientational ordering effect is stronger in the liquid phase than in the vapor phase. An examination of the energetics reveals that, in the presence of an electric field, the interactions with the first and second solvation shells become less favorable but these are outweighed by a larger increase in the favorable long-range interactions with more distant molecules and the field.
采用吉布斯系综蒙特卡罗模拟方法研究了中等强度电场对水、甲醇和二甲醚饱和相的汽液共存曲线以及结构和能量性质的影响。与无电场情况相比，施加 0.1 V/A 的电场会使所有三种化合物的临界温度和正常沸点分别升高约 3%，而临界密度则分别降低甲醇和二甲醚 1%，水 3%。对于仅在液相中施加电场的特殊情况，T(C)增加 4%，rho(C)降低 13%，这些效应被放大。对于仅在气相中施加电场的情况，则会看到相反的效果，T(C)降低 4%，rho(C)增加 12%。结构分析表明，施加电场后径向分布函数几乎没有变化，但取向有序度大大增加。在液相中，取向有序效应比在气相中更强。对能量学的研究表明，在电场存在的情况下，与第一和第二溶剂化壳层的相互作用变得不那么有利，但这被与更远的分子和电场的有利长程相互作用的更大增加所抵消。
