This in turn implies a maximum simulation time. Stretching deforms the lattice, but at a certain time the stretched lattice is identical to the initial unstretched lattice. This means the stretched lattice can be mapped back onto the original lattice shape, without any discontinuity in the interatomic energies. Details of Dr Todd and Dr Daivis's work are described in the paper 'Nonequilibrium molecular dynamic simulations of planar elongational flow with spatially and temporally periodic boundary conditions', which is scheduled for publication in Physical Review Letters. The figures demonstrate the evolution of an fcc Kraynik-Reinelt lattice under planar elongational flow as a function of time.
Contraction takes place in the y-direction.