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Thursday, May 16

Three Vignettes on Ligand Stabilized Nanoclusters

Chris Ackerson, Colorado State University, Ft. Collins
Chemical Sciences Division Seminar
10:00 AM — 11:00 AM, Chemical and Material Sciences Building (4100), Room C-201
Contact: Deen Jiang (jiangd@ornl.gov), 865.574.5199

Abstract

Metal clusters and nanoparticles can occur in a 'magic number' series, where especially stable, or 'magic' numbers of metal atoms correspond to the total filling of geometric or electronic shells. For most metals, electronic shell closing dominates the stability of smaller clusters while geometric shell closing stabilizes larger clusters. In the present talk, we investigate the transition from electronic to geometric shell closing for thiolate protected gold clusters, and we explore the consequences of manipulating the electron count in electronically stabilized clusters, in terms of both stability and magnetism, as well as potential applications that arise from altering the electron count. Finally, we present a structural investigation into the reactivity of the ligand shell that protects these clusters from coalesence, discovering which ligands are most exchangeable and proposing a mechanism for ligand exchange. This work is important because ligand exchange reactions are commonly used to incorporate nanoparticles into more complex devices and applications.