| dc.contributor.author | Martell, Jaime Michael. | en_US |
| dc.date.accessioned | 2014-10-21T12:36:50Z | |
| dc.date.available | 1995 | |
| dc.date.issued | 1995 | en_US |
| dc.identifier.other | AAINN05283 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55065 | |
| dc.description | Geometries for the molecules in the series $\rm C\sb2H\sb{n}F\sb{6-n}$ (n = $0-6$), and the radicals produced by homolytic cleavage of the C$-$C and C$-$H bonds, have been optimized at the HF/6-31G(d) and MP2/6-31G(d,p) levels. Total energies were calculated with inclusion of electron correlation, up to the MP2/6-311G(d,p) level for all species, at the MP4/6-311G(d,p) level for species with less than four fluorines, and at the G2 level for species with less than three fluorines. The C$-$C and C$-$H bond dissociation energies are reported as D$\sb0$(298 K). The C$-$C bond dissociation energies exhibit three interesting trends, two of which may be rationalized in terms of electronegativity arguments. The C$-$H bond dissociation energies indicate that C$-$H bonds can be stabilized by an inductive effect from the $\beta$-group. Inclusion of electron correlation in the geometry optimizations improves the geometrical parameters, in particular lengthening the C$-$F bonds, and improves the total energies, but has little effect on the bond dissociation energies. The hyperfine structure in the ethyl radicals was calculated using density functional theory, at the MP2/6-31G(d,p) optimized geometries, giving good agreement with experiment in most cases where comparison is possible. | en_US |
| dc.description | The reactions of the title molecules with hydroxyl radicals have been investigated by optimizing the transition state geometries at the HF/6-31G(d) level, and also at the MP2/6-31G(d,p) level for species with less than four fluorines, and calculating energies at the MP2/6-311C;(d,p) level, at MP4/6-311G(d,p) for species with less than three fluorines, and at the G2 level for species with less than two fluorines. Inclusion of electron correlation in the geometry optimizations gives an earlier transition state. The calculated activation barriers and reaction enthalpies are affected by substitution patterns and the level of theory used. | en_US |
| dc.description | Properties of the bond critical points for all species were also calculated. Charge development in the course of the reactions was monitored using Mulliken population analysis at four levels of theory, and Bader population analysis at the highest common level of theory. As with all the results presented, electronegativity plays a dominant role in the observed trends. | 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 | Ab initio studies of fluorinated ethanes: Electronic and energetic properties and reactions with hydroxyl radicals. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
