| dc.contributor.author | Wetmore, Stacey Dawn. | en_US |
| dc.date.accessioned | 2014-10-21T12:35:49Z | |
| dc.date.available | 1999 | |
| dc.date.issued | 1999 | en_US |
| dc.identifier.other | AAINQ49299 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55682 | |
| dc.description | Perhaps the most important application of theoretical chemistry is the study of radicals or molecules with one or more unpaired electrons. Experimental information about radicals can be obtained by measuring the hyperfine coupling constants (HFCCs) of various atoms within the molecule of interest. However, experimental HFCCs yield very little information about the nature of the radical. Through comparison of theoretically calculated HFCCs to those obtained experimentally, the radical structure can be revealed and other electronic properties of the system can be obtained. This thesis concentrates on studies involving accurate calculation of HFCCs and their application to specific chemical and biochemical problems. | en_US |
| dc.description | The first component of the thesis reports a study of peroxyl radicals, which are of interest due to their involvement in biological and industrial processes. Emphasis was placed on the calculation of accurate oxygen HFCCs. The peroxyl studies elucidated the best method for the calculation of accurate oxygen HFCCs. Since poor agreement was observed with DFT for small inorganic peroxyl radicals, a subset of these species was examined through the use of a combined quantum mechanics and molecular dynamics technique. This method, which accounts for matrix and vibrational effects, cannot correct for the failure of DFT to sufficiently describe the geometry of these radicals. | en_US |
| dc.description | The accurate methods for the calculation of HFCCs were then applied to an investigation of the radicals formed upon irradiation of DNA, and this study comprises the second component of the thesis. DNA radicals are of interest due to the decrease in the ozone layer and the increase in the use of radiation therapy. Studies were performed on all four DNA bases, as well as the sugar moiety. The results for some of the bases (thymine, adenine and guanine) are in good agreement with experiment indicating that a sufficient level of theory was implemented. For cytosine, however, differences were found between the theoretical and experimental results and a new mechanism was proposed for radiation damage to this base. This new mechanism indicates that the surrounding water molecules play an important role in the radiation damage. All of the calculated data for the DNA bases and the sugar group were then used to generate a model for radiation damage in DNA which encompasses the bases, the sugar-phosphate backbone and the surrounding water molecules. (Abstract shortened by UMI.) | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1999. | 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 | The calculation of accurate electronic properties of biological radicals. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
