title: Impact-induced cleaving and melting of alkali-halide nanocrystals.
abstract: Impact of nanocrystalline alkali-halide clusters against solid surfaces causes them to fission exclusively into low surface-energy fragments. In time-of-flight scattering experiments, this process appears at an impact energy so low that it must result from a single-step cleavage of the nanocrystal along low surface-energy cleavage planes. At higher energies (more than 1 electron volt per atom), a crossover occurs to an entirely different behavior-evaporative cascades that proceed irrespective of the structureenergetic properties of the fragments. These cascades, and the approximately linear scaling of the crossover energy with cluster size, are characteristic of impact-induced transformation of the cluster to a molten state. Collision with the high-rigidity surface of silicon gives a substantially greater cleavage probability than the soft basal-plane surface of graphite.
authors.forename: R D
authors.initials: RD
authors.lastname: Beck
authors.forename: P S
authors.initials: PS
authors.lastname: John
authors.forename: M L
authors.initials: ML
authors.lastname: Homer
authors.forename: R L
authors.initials: RL
authors.lastname: Whetten