In this paper, we give further discussions about our new method of bond spherical har-monics with equal number of near neighborst, and study the molten salt LiCl and itsquenching process by means of molecular dynamics simulation. The bond order parametersQ_l at different temperatures are calculated by averaging the Q_l values of the computer-generated instantaneous configurations at each time-step. By consulting the Q_l histogramsof the linear combination models with a parameter of square deviation σ we find that theQ_l Listograms from the simulation and those from the combination model with 90% localtetrahedron structure are very similar. The results indicate that the local bond orientationin the quenched LiCl system tends strongly to be tetrahedron. The local bond-orientationalorders in the quenching process can be described by the same linear combination, but thesquare deviation varies with the temperature. The square deviation decreases with thelowering of temperature and drops rapidly when the glass transition takes place. The bondangle distributions are also calculated and it is found that the angles gather about 109°(the=bond angle of tetrahedron) and the peaks of the distributions Lave a wider spread as temper-iature increases, in accordance with the results from Q_l.
展开▼
