Extending Topological Constraint Theory to Glass Networks with Hydrogen Bonding

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Bloom, A. (2023). Extending Topological Constraint Theory to Glass Networks with Hydrogen Bonding. Unc Charlotte Electronic Theses And Dissertations.
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Abstract

Topological constraint theory has been successful in providing a simple model forthe liquid-glass transition in covalent bond bending networks. However, it is lim- ited to networks where all bonds are quenched and possess equivalent potential well depths. This limitation makes it difficult to model glass networks with heterogeneous bonds such as hydrogen bond networks. By adding a single adjustable parameter to model hydrogen bonds, topological constraint theory can be extended to model glass networks with both quenched (covalent) and flickering (hydrogen) bonds. This parameter is the time scale of observation, and it is implemented by calculating hy- drogen bond probabilities by time averaging over the recent past using data from molecular dynamics simulation. The rigidity properties are quantified with the peb- ble game algorithm for body-bar networks to identify rigid subgraphs. Molecular dynamics trajectory data is mapped into a generic graph topology for a rigidity anal- ysis. The hydrogen bond dynamics are characterized with correlation functions, and a method is presented for determining the optimal geometrical hydrogen bond defini- tion. Further, it will be shown that spatial-temporal correlations present in molecular dynamics simulations shift the rigidity percolation threshold to lower mean coordina- tion numbers. It is found from rigidity percolation and scaling theory that a second order rigidity transition is driving the liquid-glass transition, and an analysis of the β critical exponent suggests that covalent bond bending networks belong to the same universality class as thermal phase transitions.

Details
Author

Bloom, Austin

Title

Extending Topological Constraint Theory to Glass Networks with Hydrogen Bonding

Physical Description

1 online resource ( pages) : PDF

Date

2023

Degree Granting Institution

University of North Carolina at Charlotte

Abstract

Topological constraint theory has been successful in providing a simple model forthe liquid-glass transition in covalent bond bending networks. However, it is lim- ited to networks where all bonds are quenched and possess equivalent potential well depths. This limitation makes it difficult to model glass networks with heterogeneous bonds such as hydrogen bond networks. By adding a single adjustable parameter to model hydrogen bonds, topological constraint theory can be extended to model glass networks with both quenched (covalent) and flickering (hydrogen) bonds. This parameter is the time scale of observation, and it is implemented by calculating hy- drogen bond probabilities by time averaging over the recent past using data from molecular dynamics simulation. The rigidity properties are quantified with the peb- ble game algorithm for body-bar networks to identify rigid subgraphs. Molecular dynamics trajectory data is mapped into a generic graph topology for a rigidity anal- ysis. The hydrogen bond dynamics are characterized with correlation functions, and a method is presented for determining the optimal geometrical hydrogen bond defini- tion. Further, it will be shown that spatial-temporal correlations present in molecular dynamics simulations shift the rigidity percolation threshold to lower mean coordina- tion numbers. It is found from rigidity percolation and scaling theory that a second order rigidity transition is driving the liquid-glass transition, and an analysis of the β critical exponent suggests that covalent bond bending networks belong to the same universality class as thermal phase transitions.

Genre

masters theses

Subjects--Topics

Physics
Condensed matter

Degree

M.S.

Keywords

Glass Networks
Hydrogen Bonding
Pebble Game Algorithm
Rigidity Theory

Subject Area

Applied Physics

Advisor(s)

Jacobs, Donald

Committee Members

Trammell, Susan
Nesmelova, Irinia

Degree Note

Thesis (M.S.)--University of North Carolina at Charlotte, 2023.

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Rights Holder Information

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Identifier

Bloom_uncc_0694N_13506

Permalink

http://hdl.handle.net/20.500.13093/etd:3281