Structural probe of a glass-forming liquid: generalized compressibility.
Structural probe of a glass-forming liquid: generalized compressibility.
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DOI：
10.1103/physreve.66.021204
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发表时间：
2001-12
期刊：
影响因子：
--
通讯作者：
H. Carruzzo;Clare C. Yu
中科院分区：
文献类型：
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作者：
H. Carruzzo;Clare C. Yu
我们引入了一个结构量来探索玻璃化转变。这个量是一个线性广义可压缩性，它完全取决于粒子的位置。我们对玻璃形成液体进行了三维分子动力学模拟，该液体由两组分的软球混合物组成。随着温度的降低(或密度的增加)，玻璃化转变处的广义压缩系数急剧下降，并且随着测量时间的增加，下降的幅度越来越大。在我们的最长测量时间，下降大约发生在模式耦合温度T(C)。线性广义压缩系数的下降发生在与比热峰值相同的温度。通过考察固有结构能随温度的变化，我们发现我们的结果与玻璃化转变的动力学观点是一致的，在这个转变过程中，体系失去了平衡。我们没有发现尺寸依赖性，也没有发现二级相变的证据，尽管这并不排除在观察到的玻璃化转变温度以下发生相变的可能性。讨论了线性广义压缩系数与普通等温压缩系数以及静态结构因子之间的关系。
We introduce a structural quantity to probe the glass transition. This quantity is a linear generalized compressibility which depends solely on the positions of the particles. We have performed a molecular dynamics simulation on a glass-forming liquid consisting of a two-component mixture of soft spheres in three dimensions. As the temperature is lowered (or as the density is increased), the generalized compressibility drops sharply at the glass transition, with the drop becoming more and more abrupt as the measurement time increases. At our longest measurement times, the drop occurs approximately at the mode coupling temperature T(C). The drop in the linear generalized compressibility occurs at the same temperature as the peak in the specific heat. By examining the inherent structure energy as a function of temperature, we find that our results are consistent with the kinetic view of the glass transition in which the system falls out of equilibrium. We find no size dependence and no evidence for a second order phase transition, though this does not exclude the possibility of a phase transition below the observed glass transition temperature. We discuss the relation between the linear generalized compressibility and the ordinary isothermal compressibility, as well as the static structure factor.