Orbital-free density functional theory requires accurate approximations for the
noninteracting kinetic energy as a functional of the ground-state electron den-
sity. For explicit functionals in real space, it has proved difficult to supersede
the quality of the gradient expansion, truncated at second order. This is partly
because the gradient expansion diverges for atomic and molecular densities.
In an effort to include information about higher-order terms in the gradient
expansion but avoid divergences, we consider resummations for the series using
Padé approximants and Meijer-G functions. To regularize terms that appear
in the denominator, we consider various damping functions, which introduces
parameter(s) that can be fit to atomic data. These results improve upon the
second-order truncation, but do not achieve the exquisite accuracy that would
be required for practical orbital-free density-functional theory calculations. / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/26169 |
| Date | January 2021 |
| Creators | Huang, Xiaomin |
| Contributors | Ayers, Paul W., Chemistry and Chemical Biology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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