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Science 23 August 1991:
Vol. 253. no. 5022, pp. 879 - 883
DOI: 10.1126/science.253.5022.879
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Articles

Impact-Induced Cleaving and Melting of Alkali-Halide Nanocrystals

RAINER D. BECK 1, PAMELA ST. JOHN 1, MARGIE L. HOMER 1, and ROBERT L. WHETTEN 1

1 Department of Chemistry, University of California, Los Angeles, CA 90024

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.

Submitted on March 22, 1991
Accepted on July 1, 1991


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Controlled Deposition, Soft Landing, and Glass Formation in Nanocluster-Surface Collisions.
H.-P. Cheng and U. Landman (1993)
Science 260, 1304-1307
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Rates of Electron Emission from Negatively Charged, Impact-Heated Fullerenes.
C. Yeretzian, K. Hansen, and R. L. Whetten (1993)
Science 260, 652-656
   Abstract »    PDF »
Dynamics of Cluster-Surface Collisions.
C. L. Cleveland and U. Landman (1992)
Science 257, 355-361
   Abstract »    PDF »


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Science. ISSN 0036-8075 (print), 1095-9203 (online)