Institut für Theoretische Physik and Center for Material Science (CMS), Technische Universität Wien, Wiedner Hauptstrasse 8-10, A-1040 Wien, Austria.
J Phys Condens Matter. 2010 Oct 20;22(41):415103. doi: 10.1088/0953-8984/22/41/415103. Epub 2010 Sep 13.
Based on extensive integral-equation calculations and on complementary Monte Carlo simulations we have investigated the phase behaviour of a class of two-dimensional model systems where particles interact via short-range attractive and long-range repulsive potentials. While for a particular member of this class of systems microphase formation has already been studied in detail in the literature, we have provided evidence that-depending on the model parameters that define this class of systems-both microphase formation and liquid-vapour transitions can be observed. For those systems that form microphases we have focused on the homogeneous fluid which is encountered at higher temperatures. By analysing the structure functions we show that already in this disordered phase a precursor of the low-temperature microphases can be identified: the wavenumber k(c), which specifies those density fluctuations against which the system becomes unstable when forming microphases at lower temperatures also plays an important role in the homogeneous phase. For those systems that show liquid-vapour phase separation we find clear trends in the position of the critical point and in the location of the coexistence branches.
基于广泛的积分方程计算和补充的蒙特卡罗模拟，我们研究了一类通过短程吸引和长程排斥势相互作用的二维模型系统的相行为。虽然对于这个系统类的一个特定成员，文献中已经详细研究了微相形成，但我们提供的证据表明——取决于定义这个系统类的模型参数——可以观察到微相形成和液-气相变。对于那些形成微相的系统，我们关注的是在较高温度下遇到的均相流体。通过分析结构函数，我们表明，在这个无序相中已经可以识别出低温微相的前体：波数 k(c)，它指定了在较低温度下形成微相时系统变得不稳定的密度涨落，在低温微相时也起着重要作用。对于那些显示液-气相分离的系统，我们发现临界点的位置和共存分支的位置有明显的趋势。
