Thesis
Reactive molecular dynamics force field for simulating hydrogenated boron nitrogen compounds and interactions with silica surfaces
Washington State University
Master of Science (MS), Washington State University
2007
Handle:
https://hdl.handle.net/2376/102935
Abstract
The discovery and development of new on-board hydrogen-storage materials that possess high storage densities as well as significant release rates at near-ambient temperatures is required for a viable hydrogen economy. One class of promising compounds currently being investigated are the borane amines NHxBHx (x=1-4). The computational framework needed to accurately and efficiently describe chemical and physical properties for large systems of NHxBHx interacting with a silica scaffold is investigated. Current computational methods are able to accurately predict the geometries, and energies for small molecules. Quantum mechanical simulations of larger molecules and solids still remain computationally very demanding. Large scale molecular dynamics simulations can accurately predict the dynamic properties of chemical systems containing thousands to millions of atoms. A reactive molecular dynamics force field, ReaxFFHBNOSi, aimed at simulating hydrogen release from ammonia boranes including interactions with a nanophase silica scaffold is developed and examined. In this study, we optimized the ReaxFF force field parameters for NHxBHx systems interacting with SiO2/SiOH. Separate BNH and SiO2/SiOH ReaxFF force fields were extended to include NHxBHx (x=1-4) as well as BNHO data in the training set. All force field parameters were based solely on first principles quantum mechanical calculations designed to characterize the various atomic environments that an atom can encounter. The training set contains bond dissociation/compression curves, angle and torsion bending data for each included cluster. ReaxFFHBNOSi was able to reproduce the corresponding quantum mechanical energies reasonably well for most structures investigated. The force field, however, failed to provide an accurate reproduction for strongly bound boron-oxygen interactions. It is anticipated that ReaxFFHBNOSi could provide an accurate description under the assumption that only weakly bound boron-oxygen interactions can occur.
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Details
- Title
- Reactive molecular dynamics force field for simulating hydrogenated boron nitrogen compounds and interactions with silica surfaces
- Creators
- Christopher E. Strickland
- Contributors
- Kirk A. Peterson (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Chemistry, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525063401842
- Language
- English
- Resource Type
- Thesis