Capping Ligands as 'Atomic Orbitals' in Superlattice Self-Assembly
Date
2018-05
Authors
Waltmann, Curt
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Research Projects
Journal Issue
Series
Department
Abstract
I present a detailed analysis of the interaction between two nanocrystals capped with ligands consisting of hydrocarbon chains by united atom molecular dynamics simulations. This work builds on previous work, which showed that the bonding of two nanocrystals is characterized by ligand textures in the form of vortices and that these results are generalized to nanocrystals of different types (differing core and ligand sizes) where the structure of the vortices depends on the softness asymmetry. In this work larger nanocrystal cores and unsaturated hydrocarbon chains are considered. Again, I provide rigorous calculations for the binding free energy, show that these energies are independent of the chemical composition of the cores, and derive analytical formulas for the equilibrium separation. In this case, unsaturated hydrocarbon chains provide extra rigidity to the chain lowering the strength of the interaction and increasing the equilibrium separation distance. Effects of larger cores, which make the cuboctahedron cores less spherical and have a lower curvature are also discussed. Overall, the results continue to support the Orbifold topological model.