dc.contributor.advisor | Ching, Wai-Yim | eng |
dc.contributor.author | Dhakal, Chandra | eng |
dc.date.issued | 2015-08-12 | eng |
dc.date.submitted | 2015 Summer | eng |
dc.description | Title from PDF of title page, viewed on August 12, 2015 | eng |
dc.description | Thesis advisor: Wai-Yim Ching | eng |
dc.description | Vita | eng |
dc.description | Includes bibliographic references (pages 57-64) | eng |
dc.description | Thesis (M.S.)--Department of Physics and Astronomy. University of Missouri--Kansas City, 2015 | eng |
dc.description.abstract | The spherical amorphous silica (a-SiO₂) nanoparticles (NPs) are constructed from a
previous continuous random network (CRN) model of a-SiO₂ with the periodic boundary.
The models of radii 12 Å, 15 Å, 18 Å, 20 Å, 22 Å, 24 Å and 25 Å are built from the CRN
structure. Then, three types of models are constructed. Type I has the surface dangling bonds
not pacified. In type II models, the dangling bonds are pacified by hydrogen atoms. In type
III models, the dangling bonds are pacified by the OH groups. These large models are used to
perform the electronic structure calculation of NPs by using the orthogonalized linear
combination of atomic orbital (OLCAO) method. The results show some trends in band gap
variation for Type I models. The trends in band gap variation for other two types are less
clear.
A series of NP models with a spherical pore in the middle of a solid NP model are
constructed and studied. Spherical pores of radii of 6 Å, 8 Å, 10 Å, 12 Å, 14 Å, 16 Å and 18
Å are introduced within the spherical model of radius 20 Å. After OLCAO calculation, it is
found that the band gap values remain constant (5 eV) up to 21.6% porosity and then
decreases with increased in porosity. The relation with thickness of the porous NP shell and
the surface to volume ratio (S/V) with the calculated band gap are studied in the same
manner and will be discussed. | eng |
dc.description.tableofcontents | Introduction -- Theoretical background -- Method -- Results and discussion -- Conclusion and future work -- Appendix A. Abbreviations | eng |
dc.format.extent | xi, 65 pages | eng |
dc.identifier.uri | https://hdl.handle.net/10355/46554 | eng |
dc.subject.lcsh | Silica | eng |
dc.subject.lcsh | Amorphous substances | eng |
dc.subject.other | Thesis -- University of Missouri--Kansas City -- Physics | eng |
dc.title | Computational Modeling of a-SiO₂ Nanoparticles and their Electronic Structure Calculation | eng |
dc.type | Thesis | eng |
thesis.degree.discipline | Physics (UMKC) | eng |
thesis.degree.grantor | University of Missouri--Kansas City | eng |
thesis.degree.level | Masters | eng |
thesis.degree.name | M.S. | eng |