Diverse Local Structures in Simulated Amorphous SiO2
Open Access
Author:
Dormier, Adam Matthew
Area of Honors:
Chemical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
Scott Thomas Milner, Thesis Supervisor Darrell Velegol, Thesis Honors Advisor
Keywords:
silica glasses simulation computational molecular dynamics local structure SiO2
Abstract:
Amorphous silica lacks the global periodic structure present in its crystalline counterparts
(quartz, tridymite, crystoballite, etc.), and this leaves open the question of what its structure actually
looks like, as well as how it can be effectively described. We apply a method rooted in
graph theory to identify and label local structural arrangements within glasses generated by molecular
dynamics (MD) simulations. The focus on atomic connectivities makes this methodology
structure-agnostic, and enables the search for recurring structural motifs within the system. We
observe the distribution of local structures over a range of temperatures which straddle the glass
transition in an effort to determine whether a relationship exists between the dynamics of the system
as it undergoes glass transition and its internal structure. To this end, we also consider the
lifetimes of the observed local structures as the temperature of the system is varied. Additionally,
we simulate glasses under various annealing conditions in order to observe the impact of the
preparation of a glass on its structure.
