Collective motion of atoms in a superheated crystal and a supercooled melt of a simple metal

Stable and metastable states of a crystal and a melt have been studied near the equilibrium crystal–melt phase transition point using a four-point correlation coefficient previously proposed to reveal collective motions of atoms in a liquid. The embedded copper atom model has been considered as an example with the molecular dynamics method. Strong hysteresis of the correlation coefficient values is detected along the paths of isochoric superheating of the crystal until its melting near the spinodal and the inverse supercooling of the melt to its crystallization. The capabilities of this coefficient for a quantitative estimate of the character of the near-range order, the degree of correlation of the motion of neighboring atoms, and the radius of action of dynamic collective effects in condensed matter are revealed.