Order parameter icosahedral

For symmetry reasons, bond order parameters with / > 4 have non-zero values in clusters with cubic symmetry and I > 6 for clusters with icosahedral symmetry. The most widely calculated bond order parameters are 1 = 4 and 1—6. Different values correspond to crystaUine materials with different symmetry, while the global values vanish in disordered phases, such as in liquids. This feature made the Q and W invariants attractive for use as bond order parameters in many applications. 

Fig. 9.35 Order parameter as a function of mass fraction for various n. The open circles are from Abraham and the closed circles are from Petsche and Grest. Here L is a measure of the membrane size, which for the open membrane is its length when it is perfectly flat and for a closed vesicle it is the length along an edge in the initial icosahedral configuration.

It is therefore worthwhile to use the non-Condon correction in other systems in which the second-order RFs is an important parameter especially in icosahedral systems. This will be the subject of future work. 

Further analysis of the computed energy parameters either requires some special symmetry such as that found in octahedral BeHe or icosahedral Bi2Hi2 or some further assumptions concerning the chemical bonding topology for less symmetrical systems in order to minimize the number of independent unknowns to be determined. In the cases of BeHe ... 

When the temperature of melt is dropping, the average value decreases the maximiun of the parameter distribution shifts to the left. However, die maximiun never moves below Wg = -0.05, and the distribution function weakly depends both on temperature and on simulated d-metal. An insignificant increase in the distribution function can be seen on die side of negative values, and, correspondingly, a decrease in the function is observed on the side of positive values, which indicates the insignificant growth of the fiaction of clusters with icosahedral and polyhedral order and the decrease of the fiaction of clusters with FCC-, HCP-and BCC-like order. 

This study presents the results of the molecular-dynamics simulation of Ni, Cu and Au in liquid and supercooled liquid states using realistic potentials of interatomic interaction. At supercooling of melt, the structure analysis of the evolution of the local cluster structure has been performed on the basis of the parameters of the orientation order of interatomic bonds and the coordination numbers. The presence of local icosahedral and... 

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