Determining the electric quadrupole moments of gas molecules from measurements of birefringence induced in the gas by an applied electric field gradient is widely recognised as being the most direct experimental technique for this purpose. This thesis presents a new molecular theory of the experiment, and also describes the apparatus used in the measurement of the quadrupole moments of a number of gases and the revisions made to the manner in which the experiment was performed. A recent eigenvalue theory of light propagation in matter has been used to derive an expression relating the induced birefringence to the electric quadrupole moment of the molecule, whether this be dipolar or not. This expression is different from that which has previously been applied to dipolar molecules. It is shown that the new expression is independent of molecular origin only if it is cast in terms of the primitive quadrupole moment, as opposed to the traceless moment. Previous work using the same set of apparatus yielded results for carbon dioxide which were significantly lower than those reported by other workers. By using the Jones calculus to re-examine the cascade of optical components used in the experiment, it was found that the previous method of performing the experiment did not completely eliminate the effects of an imperfect retardance in the quarter-wave plate used, nor of strain-induced birefringence in the windows of the the cell containing the gas. These effects could cause results to be underestimated by as much as 8%. It is shown that a better method of performing the experiment is to amplify the optical signal by deliberately offsetting the analysing prism, rather than the quarter-wave plate as was previously done. The results of measurements made using this technique are reported for carbon dioxide, carbon monoxide, nitrogen, ethene, chlorine, and boron trifluoride. The measured quadrupole moment of carbon dioxide is in good agreement with the most recent values found by other workers using a similar experiment, and with the latest theoretical value of this quantity. / Thesis (PH.D.)-University of Natal, Pietermaritzburg, 1993.

Thesis (Ph.D.)--Boston University. / Hartree-Fock self-consistent field calculations of the Roothaan (linear combination of atomic orbitals - molecular orbital) type have been carried out on an electronic computer for LiH and Li2 using an extended basis set of Slater type atomic orbitals. Configuration interaction calculations result in a total molecular energy of 99.34% of the experimental value, and a dissociation energy of 89.33% of the experimental value in LiH. Similar calculations in Li2 result in 99.40% and 89.9%, respectively, for these two numbers. The energy of atomic Li, which enters the dissociation energy calculation, is calculated to comparable accuracy (99.42%). [TRUNCATED]

Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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Thesis (Ph.D.)--Ohio University, March, 2009. / Release of full electronic text on OhioLINK has been delayed until April 1, 2010. Includes bibliographical references (leaves 188-200)

Thesis (Ph.D.)--Ohio University, March, 2009. / Title from PDF t.p. Release of full electronic text on OhioLINK has been delayed until April 1, 2010. Includes bibliographical references (leaves 188-200)

The theory of the quadrupole interaction in nuclear magnetic resonance spectroscopy and relaxation measurements is presented in detail, with applications to ²H-NMR studies of order and dynamics in bilayers of deuterated lipids. Investigations of lipid-protein interactions in reconstituted membrane systems and intact biological membranes are reviewed. An experimental program is described which uses a synthetic amphiphilic polypeptide, with known geometry and variable length, to isolate questions about the geometrical interpretation of orientational order in lipid-protein interactions. A report is presented of an investigation of the effects of this polypeptide, Lys₂-Gly-Leu₂₀-Lys₂-Ala-amide, on the mixed bilayer system: Dimyristoylphosphatidylcholine Di-per-deuterio-myristoylphosphatidic Acid. The addition of the peptide was found to have little effect (≤5%) on the first and second moments of the distribution of quadrupole splittings in the liquid crystalline phase. Similarly, the spin-lattice relaxation time constants were affected by ≤10% in the liquid crystalline phase. The time constant for the decay of the quadrupole echo decreased dramatically above the phase transition with the addition of peptide, a phenomenon which is explained in terms of the presence of a new slow motion in the lipid-peptide systems. A simple model of the slow motion induced by the peptide is proposed, in which the lipid molecules undergo a rapid exchange between boundary and bulk sites. An effective correlation time is determined from an average over the rotations on each of these sites. Using this model, estimates are made of the change in the second moment brought about by the onset of the rotations, and. of the number of binding sites on the peptide. These estimates are found to be in agreement with independent measurements of the change in the second moment, and the number of binding sites is within the range predicted by simple considerations of charge balance. The change in the lineshape with the variation of the spacing of the pulses in the quadrupole echo experiment was investigated, and it was determined that the transverse relaxation time constants have a slight orientation dependence. It was also determined that the addition of the peptide has no significant effect on the variation of the lineshape. Some experiments which could answer some of the questions raised by these results are suggested. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Thesis (Ph.D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph.D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

No description available.