COLL 467 |
| Charles T. Campbell, Chemistry Department, Chemistry Department, University of Washington, Box 351700, Seattle, WA 98195-1700 |
| Heats of adsorption of metal atoms have been measured calorimetrically on Mo(100), Si(100), MgO(100). A pulse of metal vapor from a chopped atomic beam adsorbs onto an ultrathin single crystal's surface, causing a transient temperature rise detected by a pyroelectric polymer ribbon touching the crystal. The differential heat of adsorption is measured versus coverage up through multilayer coverages. The data provide the metal-substrate bond energy (BE), the adhesion energy and the interfacial energy. The heats also provides evidence for island-island repulsion when 2D islands strain the lattice nearby, as with Ag on Si(100)-2x1. In cases where 3D metal nanoparticles nucleate and grow in size, the data also provide metal nanoparticle energetics versus particle size. These data show that the surface energy of metal particles <4 nm is dramatically larger than that of large particles. |
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Symposium in Memory of Arthur W. Adamson
8:30 AM-11:50 AM, Thursday, April 1, 2004 Marriott -- Orange County 3, Oral
Division of Colloid and Surface Chemistry |