Ab initio electronic structure calculations. A. High-temperature bismuth oxide cluster models. B. Characterization of 1,2-HX elimination reactions from haloethanes. C. Frequency dependent polarizability and second order hyperpolarizability of polyacetylene
The results from ab initio electronic structure calculations are presented. In the first chapter, the author presents the results from SCF and CISD calculations on BiO[sub 6][sup [minus]n] (n = 7, 8, 9) clusters designed to model the Ba[sub 0.6]K[sub 0.4]BiO[sub 3] superconductor. The orbital description and energy differences produced in this model agree well with photoemission and band structure results. The results show that doping produces holes that predominantly reside on oxygen sites. The second chapter is concerned with an extensive characterization of 1,2 elimination reactions from halogenated ethanes via SCF and MP perturbation calculations. The results show differences in geometry, atomic charges and electrophilicity of HX in the elimination/addition TS's involving X = F compared with TS's found for the other halogens (Cl, Br, and I). The F substituents are electron releasing when going from the reactant to the TS, while Cl releases a greater amount of electrons at the TS in HCl elimination as compared to the reactions involving the loss of HF. It is predicted that Br and I should react similarly to Cl. Contrary to what has been proposed in the literature, the polarity of the CCl bond at the TS is large and contains a negatively charged Cl atom. The electrophilicity of HF and HCl in Markownikoff type addition to alkenes are independent of [alpha]-substituents although HF addition is less electron withdrawing than HCl. The final chapter gives dynamic polarizabilites and hyperpolarabilities of polyenes ranging from 4 to 22 carbon atoms and static properties for oligomers in the range between 4 to 30 carbon atoms. The calculations were performed with the use of a 6-31G basis set at the TDHF level of theory. Various extrapolation methods are used for obtaining infinite chain (i.e. polyacetylene) estimates to the above properties.
- Research Organization:
- California Univ., Santa Barbara, CA (United States)
- OSTI ID:
- 7263608
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Aromatic substitution in the gas phase. On the mechanism of the dehalogenation reactions of halobenzenes and dihalobengenes promoted by gaseous Bronsted acids. [Gamma radiation]
Ab initio molecular orbital study of substituent effects in vaska type complexes (trans-IrL{sub 2}(CO)X): Electron affinities, ionization potentials, carbonyl stretch frequencies, and the thermodynamics of H{sub 2} dissociative addition
Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BISMUTH OXIDES
ELECTRONIC STRUCTURE
ORGANIC HALOGEN COMPOUNDS
CHEMICAL PROPERTIES
POLYENES
POLARIZABILITY
HIGH-TC SUPERCONDUCTORS
BISMUTH COMPOUNDS
CHALCOGENIDES
ELECTRICAL PROPERTIES
HYDROCARBONS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SUPERCONDUCTORS
664100* - Theory of Electronic Structure of Atoms & Molecules- (1992-)
400201 - Chemical & Physicochemical Properties