| dc.contributor.author | Wang, Jian. | en_US |
| dc.date.accessioned | 2014-10-21T12:37:12Z | |
| dc.date.available | 1995 | |
| dc.date.issued | 1995 | en_US |
| dc.identifier.other | AAINN08820 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55095 | |
| dc.description | On the basis of electron density distributions, density functional theory (DFT) is critically and systematically compared with conventional high-level ab initio methods. Relative to the results based on the local spin density approximation (LSDA), gradient-corrected DFT methods improve the electron density toward the high-level ab initio results, but still overestimate the electron correlation effect due to the use of approximate exchange and correlation functionals. | en_US |
| dc.description | Electron densities, calculated from various quantum chemical methods, are used to study the electronic structures of Jahn-Teller and Rydberg molecules. The symmetry of the electron density is shown to be related to the distortion direction of a Jahn-Teller unstable molecule. The atomic energy components, which are calculated from the electron density distribution associated with an atomic basin, provide insight into the structures of Rydberg molecules. | en_US |
| dc.description | The quantum mechanically calculated atomic charges are used to set up flexible charge models for molecular dynamics (MD) simulations. The significance of flexible charges in MD simulations is demonstrated in terms of radial distribution functions, time correlation functions and other quantities. The systems selected for study include trans-stilbene in methanol solution and liquid methanol. Also, an assessment of a new series of potential calcium antagonists is made on the basis of the ab initio calculations and molecular dynamics simulations. | en_US |
| dc.description | The successful application of quantum mechanical calculations to MD simulations is also demonstrated by means of a new MD method, in which quantum mechanical force fields are used directly. This approach is applied to study in detail the internal vibrational motions of methanol, the flexibility of the benzene ring, and quantum tunnelling in CD$\sb{4}\sp{+}$ and CH$\sb{4}\sp{+}$. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1995. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Chemistry, Physical. | en_US |
| dc.title | Electron densities and quantum mechanical force fields applied to electronic and molecular structures. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
