  What lattice Lennard-Jones (LJ) solid favors, the lattice identification of
simulated system and the microstructures of liquid and non-crystalline solid
are three important questions in condensed physics and material science and are
addressed in this paper. Both the crystallization and non-crystallization of LJ
particles have been investigated by molecular dynamic (MD) simulation without
setting any initial Bravais lattice. To identify the Bravais lattice of
simulated system, two distribution functions of both the angles between one
particle and its nearest neighbors and the distances between particles have
been proposed. The final identification can be made by comparing these two
calculated distribution functions with those of ideal Bravais lattices and
checking the particle arrangement of simulated system. Our results have shown
that simulated systems show either the face-centered cubic (fcc) lattice or the
hexagonal close-packed (hcp) lattice. The microstructure of non-crystalline
system is similar to that of LJ liquid at a temperature near the
crystallization temperature, and shows no order of the second nearest neighbors
in comparison with that of crystalline system. This paper has proposed a new
way of investigating the microstructure of material and its evolution, and
paved the way for MD simulation of large scale particle system consisting of
more than one million particles.
