标题： 脆弱氢键液体中结构不均匀性的实验指示 显示英文标题

标题： Experimental Indication of Structural Heterogeneities in Fragile Hydrogen-bonded Liquids

摘要： 我们首次在分子脆弱玻璃形成体中对静态结构因子主峰以下显著位置出现的“前峰”进行了实验表征。 通过在高压力（高达300 MPa）下对m-甲苯胺和m-氟苯胺进行弹性中子散射实验，研究了该前峰的温度和密度依赖性。 前峰强度随温度降低而增加，但在压力增加时保持不变，其位置和宽度大致相同。 这些特性与网络玻璃的“第一尖锐衍射峰”观察到的特性相反。 借助蒙特卡罗模拟分析了该现象的起源。 我们将前峰归因于氢键引起的异质性（或团簇），其有限尺寸是由于苯环之间的排斥效应阻止了氢键网络的扩展。 最后考虑了该现象对接近玻璃转变温度的液体动力学的影响。 显示英文摘要

摘要： We present the first experimental characterization in molecular fragile glassformers of a 'prepeak that appears significantly below the main peak of the static structure factor. The temperature and density dependences of this prepeak are studied via elastic neutron scattering experiments under high pressure (up to 300 MPa) in m-toluidine and m-fluoroaniline. The prepeak intensity increases with decreasing temperature, but it remains constant with increasing pressure while its position and width stay roughly the same. These features are opposite to those observed for the 'first sharp diffraction peak' of network glasses. The origin of the phenomenon is analyzed with the help of Monte Carlo simulations. We associate the prepeak to hydrogen-bond-induced heterogeneities (or clusters) whose limited size results from exclusion effect between benzene rings that prevents the extension of a hydrogen-bond network. Implications for the dynamics of the liquid close to the glass transition are finally considered.