The Intermediate Phase in Network Glasses

这位资深的杰出的PI研究眼镜的性质，但是在网络模型的框架内。在这个着眼于网络连通性等几何细节的观点中，网络是通过将模型中最重要的力设置为无穷大而将其余力设置为等于零来推导的。所得到的模型可以通过大量的粒子在计算上进行管理。在该模型中，在一个临界配位数(作为平均配位数的函数)下(通常共价玻璃的配位数较大，而聚合物玻璃的配位数一般较小)，状态演化为刚性和应力态。然而，数值结果表明，存在一个刚性态但不受应力的中间态。这笔拨款支持网络玻璃这一中间阶段的进一步工作。最近关于硫化物玻璃的实验为这种性质的中间相提供了初步证据。这位资深的杰出的PI在涉及玻璃的广泛研究领域中处于领先地位。特别是，在他相信可以使用几何模型来研究玻璃的许多性质的指导下，即由棍子和球制成的模型，他注意到玻璃中存在奇怪的相，这可能是在实验中看到的。从玻璃对平均配位数(给定原子可能连接的原子数)的依赖来看，有两个相，一个是玻璃具有小的配位数，没有刚性和累积的应力，而在大的配位数时，玻璃是刚性的，它有累积的应力。在相变附近，以及一系列配位数的临界值附近，有一个中间相对应着一个刚性但无应力的玻璃。他计划研究状态的可观察特性。

0078361ThorpeThis senior and distinguished PI works on properties of glasses but in the framework of a network model. In this view, which focuses on the geometric details such as network connectivity, the network is derived by putting the most important forces in the model to be infinite and the rest are set equal to zero. The resulting model is computationally manageable with a large number of particles. In this model, at a critical (as a function of) average coordination number (generally covalent glasses have large coordination number while the polymeric glasses in general have smaller coordination number), the states evolve in to a rigid and stressed state. However the numerical results show the existence if an intermediate state which is rigid but not stressed. This grant supports further work on this intermediate phase of a network glass. Recent experiments in chalcogenide glasses give preliminary evidence for an intermediate phase of this nature.%%%This senior and distinguished PI is a leader in the broad field of study involving glasses. In particular, guided by his belief that many properties of glasses can be studied using a geometric model, i.e. one made from sticks and balls, he has noticed the presence of curious phase of glass which may have been seen experimentally. Looking at glasses from their dependence on an average coordination number (number of atoms that a given atom may be connected to) there are two phases, one where the glass has a small coordination number, no rigidity and no accumulated stress while at large coordination number, the glass is rigid and it has accumulated stress. Near the transition, and a range of coordination number around the critical value, there is an intermediate phase corresponds to a rigid but unstressed glass. He plans to look at the observable properties of state.***