Crystallization of dense hard sphere packings - Competition of hcp and fcc close order
Crystallization of dense hard sphere packings - Competition of hcp and fcc close order
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DOI：
10.1016/s0167-7322(01)00346-4
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发表时间：
2002-04-01
影响因子：
6
通讯作者：
Troadec, JP
中科院分区：
文献类型：
--
作者：
Luchnikov, V;Gervois, A;Troadec, JP
我们研究了致密硬球填料（16000 个球体）的大型分子动力学模型中的结晶动力学。晶序的敏感测量是旋转不变 Q(6) 系数，由 Steinhardt 等人首先提出。 [14] 对于原子的邻居。结晶的倾向取决于堆积分数和样品的制备方式。最终的晶体是fcc类型的。然而，hcp 对称性存在于中间步骤中；实际上，hcp 和 FCC 簇的混合物可能会共存很长时间。晶序的出现和传播是通过局部 Q(6) 参数来研究的，该参数由最接近给定原子的 12 个原子构成。对于给定的填充分数C，Q(6)的分布函数中的fcc峰在结晶过程中增加并保持相同的形状，与结晶状态和样品最初制备的方式无关。研究了面心立方原子簇的大小随时间的变化。
We investigate the kinetics of crystallization in large molecular-dynamics models of dense hard sphere packings (16000 spheres). A sensitive measure for crystalline order is the rotationally invariant Q(6) coefficient, first introduced by Steinhardt et al. [14] for the neighbors of an atom.The propensity to crystallize depends on the packing fraction and on the way the sample is prepared. The final crystal is of the fcc type. However, the hcp symmetries exist in an intermediate step; practically, mixtures of hcp and fcc clusters may coexist for a long time. The appearance and propagation of the crystalline order is studied by means of the local Q(6) parameter, constructed from the 12 atoms the closest to a given atom. For a given packing fraction C, the fcc peak in the distribution function Of Q(6) increases during the crystallization and keeps the same shape., independently of the state of the crystallization and of the way the sample was initially prepared. The size of fcc atom clusters is studied as, a function of time.