Tailoring and Scaling Energetic Aluminum Clusters into Cluster Assembled Materials

Open Access
Author:
Smith, Jordan Cesar
Graduate Program:
Chemistry
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
May 07, 2015
Committee Members:
  • Albert Welford Castleman Jr., Dissertation Advisor
  • Nicholas Winograd, Committee Member
  • John B Asbury, Committee Member
  • Robert John Santoro, Special Member
Keywords:
  • aluminum
  • cluster
  • reactivity
  • matrix isolation
  • cavity ring down spectroscopy
Abstract:
As matter decreases in size the importance of a single atom increases exponentially. The properties of clusters, molecules with less than 100 atoms, will change drastically with the addition or removal of a single atom. Clusters have been shown to have properties that mimic other elements and properties that are completely unique. Cluster assemblies could enable the tailoring of precise properties in materials, providing cheap replacements for expensive elements, or novel materials for new applications. Aluminum clusters show great potential use in many applications including energy and catalysis. This work is focused on gaining a better understanding of how geometry and electronic structure affect aluminum cluster reactivity and how useful clusters might be successfully assembled into materials. The effects of doping aluminum cluster ions with boron atoms are reported and show that the addition of a single boron atom usually stabilizes the cluster while adding more boron atoms results in a breaking of symmetry and destabilization. A new analytical technique, matrix isolation cavity ring-down spectroscopy (MICRDS) was developed to help bridge the gap between gas phase cluster studies and condensed phase cluster materials. Molecules are trapped in an inert matrix and studied using cavity ring-down spectroscopy. MICRDS has the potential to also combine clusters into small stable units that would maintain their advantageous gas phase properties.