Proton magnetic resonance has been studied in methane and its deuterated modifications. Measurements of relaxation time were carried out at a frequency of 30 Mc/sec. using pulse techniques. The spin-lattice relaxation time has been measured in liquid and solid samples of CH₄, CH₃D, CH₂D₂ and CHD₃ between 110°K to 56°K. The simplest possible interpretation of our results in both the liquids and solids is that only one mechanism, that associated with the inter-molecular interactions, is probably predominant in causing relaxation. The spin-rotational and intra-molecular dipolar interactions do not seem to contribute appreciably to relaxation. The effect of dissolved paramagnetic ions has also been studied in samples of CH₄ between 110°K - 78°K and we have developed a very simple and reliable technique for obtaining oxygen-free samples in order to study T₁ in pure samples because T₁ has been found by us to be very sensitive to small, amounts of oxygen. The results verify the invers proportionality of T₁ to the oxygen concentration. The spin-spin relaxation time T₂ has been measured in liquid and solid samples between 110°K and 56°K. The results show that the line shape is predominantly due to inter-molecular interactions. Furthermore the resonance line has a gaussian shape at temperatures below 65°K and changes to a Lorentzlan shape at higher temperatures. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

A field modulated super-regenerative spectrometer was constructed. The theory of its operation was developed and put to test by observing the pure quadrupole resonance of Chlorine 35 in Para - di-chlorobenzene powder at room temperature. The spectrometer's operation is closely related to the quadrupole transient effects. So another experiment was done to measure the amplitude and the decay time constant of Free Induction Signal in Para-di-chlorobenzene as a function of pulse width and magnetic field, using a pulsed r.f. transmitter, constructed for this purpose, The results of this experiment were then applied to the theory of the spectrometer to explain its behaviour. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Nuclear magnetic resonance and infra-red studies have been made of various clathrate compounds. The purpose of the investigations was to examine the extent of molecular motion which the enclathrated molecule^ may undergo. It has been shown that the benzene molecule in the clathrate with Nickel Ammonium Cyanide rotates about the six-fold axis at room temperature. The existence of shifts in the infra-red spectrum of the enclosed molecule has been confirmed but the assignment of the absorption bands at 1573 cm-¹ and 1165 cm-¹ as the Raman active E[subscript 2g] vibrations is incorrect. Studies on the quinol clathrates of methane, fluoroform, methyl alcohol and methyl cyanide and the clathrate of sulphur hexafluoride in Dianin's compound (4-p-hydroxyphenyl-2,2,4-trimethyl chroman) infer that isotropic motion of the enclathrated molecues occurs at 77°K. The infra-red spectra of these clathrates and of quinol 0-d₂ have been examined. Nuclear magnetic resonance investigations of molecular motion in weak charge transfer complexes are reported. In the dioxane complexes of bromine and mercuric chloride the structure is rigid at room temperature. In the complexes with antimony trichloride and silver perchlorate the dioxane molecule is reorienting about the O-O axis at 298°K but is rigid at 77°K. Rotation of the benzene ring at 25°C in the complex AgClO₄.C₆H₆ suggests that the reported distortion of the benzene ring may be incorrect. At low temperatures the agreement between the theoretical and and experimental second moments shows that the essential features of the structure are correct. The implication of the infra-red studies of other workers are discussed. Reorientation of both aromatic rings in the complex of benzene and hexafluorobenzene occurs down to low temperatures. The potential barrier hindering rotation of the hexafluorobenzene molecule is estimated to be 1.1 kcal/mole. / Science, Faculty of / Chemistry, Department of / Graduate

In this thesis a theoretical study is made of the resonance spectra of the B¹¹ nuclei in a single crystal of Kernite (Na₂B₄0₇.4H₂0) whose, quadrupole moments interact with the electric field gradient at the nuclear sites in the crystal in the presence of an external magnetic field when the magnetic and quadrupole interaction energies are comparable. Using the results of the high field work of Waterman and Volkoff, energy levels and transition frequencies have been calculated numerically using the University of British Columbia ALWAC-III-E digital computer over a range of magnetic fields in the region intermediate between the limiting cases of pure quadrupole energy levels slightly perturbed by magnetic interactions and Zeeman energy levels slightly perturbed by quadrupole interactions. The magnetic field was taken to be oriented in the plane perpendicular to the two-fold symmetry axis of the crystal and the calculations were carried out for different orientations of the external magnetic field in steps of 30°. A general theory has been developed for the calculation of signal intensities in the case of crossed coil spectrometer (induction method) and has been applied to the present case. The signal intensities for absorption type spectrometers are proportional to the transition probabilities, and results are given for the case of Kernite which enables one to compare the expected signal intensities of absorption spectrometers with those of induction spectrometers. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Methods of setting up generalized Bloch equations governing the time dependence of macroscopic magnetization for a system of nuclei of spin I, in given magnetic and electric fields, have been proposed for the degenerate case by Bloom, Hahn and Herzog and by Lureçat, and for the non-degenerate case by Bloom, Robinson and Volkoff. In this thesis an attempt is made to give a unified discussion of these methods by utilizing the density matrix formalism and to demonstrate the interrelationship between them. Relaxation effects are not considered. The general theory is developed in terms of the density matrix formalism and is applied to the non-degenerate and the degenerate cases. The results are discussed and compared with those of the previous investigators. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

This thesis describes the experimental investigation of the complete resonance absorption spectrum of B¹¹ nuclei in a single crystal of kernite (Na₂B₄O₇.4H₂O) placed in a uniform external magnetic field, and its interpretation in terms of the perturbation of the nuclear Zeeman energy, levels by the interaction of the nuclear electric quadrupole moment with the crystalline electrostatic field gradient. Some observations on the Na²³ spectrum in kernite are also included. The present experiment is one of a series carried out in this laboratory on the study of such nuclear electric quadrupole interactions. In the two previous cases studied, those of Li⁷ and Al²⁷ in LiAl(SiO₃)₂ (spodumene), the atomic positions and symmetry of the crystal are such that there is only one kind of site for each of the two nuclear species studied as far as the electric field gradient is concerned. For both these cases the simplest possible spectrum of 2I lines was observed for any orientation of the crystal with respect .to the erternal magnetic field. In the Li⁷ case first order perturbation theory was adequate to explain the observed spectrum while second order theory was required for the Al²⁷ spectrum. In order to study in detail one case of a complex spectrum due to nuclei of the same species in different non-equivalent positions in the unit cell, the methods of radio frequency spectroscopy used for the previous experiments were applied to the study of the complete B¹¹ [formula omitted] spectrum in kernite (Na₂B₄O₇.4H₂O) in a magnetic field of 7060 gauss. The B¹¹ resonance absorption spectrum was observed in detail as the crystal was rotated about three mutually perpendicular axes. Eleven lines due to B¹¹ were observed when the symmetry axis of the crystal was perpendicular or parallel to the magnetic field, and twenty-one lines were observed in all other orientations of the crystal. In addition to some of these lines were slightly split in some orientations of the crystal. This observed number of lines was interpreted by assuming four essentially non-equivalent boron sites in the crystal with four others obtained from them by a 180° rotation about the b axis of the monoclinic kernite crystal. This interpretation drawn directly from the experimental data is in agreement with the previously proposed symmetry of the crystal on the basis of X-ray data. The complete set of properties of the quadrupole coupling tensor [formula omitted] was determined at each of the non-equivalent B¹¹ sites. The values of the quadrupole coupling constants [formula omitted] at the four essentially non-equivalent sites are .645±.003, .588±003, 2.563±007, 2.567±.010 Mc/s, and the corresponding asymmetry parameters are .54±.01, .60±.02, .163±.010, .116±.010. The orientation of the electric field gradient tensors at the four nuclear sites are given in the thesis. The preliminary investigation of the Na²³ spectrum in kernite leads to a direct contradiction of the positions for these atoms proposed on the basis of earlier X-ray data. Whereas the previously proposed structure postulates three non-equivalent sodium positions, two of which are on axes of symmetry, the Na²³resonance spectrum shows definitely that there are essentially two non-equivalent sodium sites neither of which is on an axis of symmetry. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Nuclear magnetic resonance studies in single crystals of thallium have been performed for the first time. The resonance frequency, line width and second moment were studied as a function of crystal orientation with respect to the magnetic field. The Knight shift parameters were determined at liquid helium and liquid nitrogen temperatures. The anisotropic Knight shift results were in disagreement with the results obtained on powder specimens by other workers. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Satellite lines originating from the first nearest neighbours have been observed on the Al²⁷ N.M.R. spectrum in dilute single crystal samples of Al-Mn and Al-Cr. The field and orientation dependence of the satellite position has revealed the quadrupole coupling constant and asymmetry parameter of [formula omitted] = 60 ± 1kHz and [formula omitted] = -0.01 ± 0.005 for Al-Cr, and [formula omitted] = 19 ± 1kHz, [formula omitted] = -0.08 ± 0.02 for Al-Mn. An anisotropic magnetic perturbation of ∆ K[₁₁₁] = -0.05 ± 0.01% and ∆ K[₀₀₁] = -(0.07 ± 0.1)% in Al-Mn is attributed to a spin density perturbation at the impurity sites. The Al-Cr results agree with those of Janossy and Gruner [18] and Minier and Berthier [22]. The satellite line observed in the Al-Mn system was also seen by Launois and Alloul [2], with approximately the same values of [formula omitted] and ∆ K. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

A series of isomeric, six-membered, cyclic phenyl phosphate esters has been obtained by column chromatography of the mixtures of isomers obtained by reaction of phenyl phosphorodichloridate with appropriate 1,3-diols. The conformational analysis of the isomers was undertaken using both ¹ʜ and ³¹p n.m.r.. The basic conformation of the 2 oxo-2-phenoxy-1,3,2-dioxaphosphorinane ring system is that of a "flattened-chair". The thermodynamic free energy difference between "chair" conformations is sufficiently large for the basic ring to exist essentially in one favoured conformation, rationalized to have an axial phenoxy substituent. The stereospecific nature of Jpoch has been confirmed by using ¹ʜ n.m.r. to determine conformations. Long-range, ⁴J, ³¹p- ¹ʜ coupling constants have been found to be stereospecific in nature and useful in facilitating assignment of conformations for methyl-substituted-2-oxo-2-phenoxy-l,3,2-dioxaphosphorinanes. Similar ring systems having different substituents at phosphorus have been studied and the conformations of these derivatives are seen to differ depending on the nature of the phosphorus substituent. The conformation of a cyclic nucleotide has been determined from its ³¹p n.m.r. spectrum. The use of computer programming techniques and hetero-nuclear double resonance techniques, greatly facilitated the analysis of the n.m.r. spectra discussed. An interesting deceptively-simple type of ABX n.m.r. spectrum has been found for many of these cyclic phosphate derivatives and the explicit analysis of this system is presented. / Science, Faculty of / Chemistry, Department of / Graduate

The nuclear magnetic resonance in single crystal magnesium has been studied at 4.2°K. The isotropic Knight shift, the anisotropic Knight shift and the quadrupole interaction have been investigated. The values for the parameters measured are K = (0.1127 ± 0.0005)%, K' = (0.0004 ± 0.0002)%, e²qQ/h = 324 ± 6 KHz. These results are compared with those of Rowland in powdered magnesium to reveal the Knight shift is independent of temperature. This contrasts directly with the behavior of cadmium. The quadrupole interaction is shown to increase by 40% as temperature is lowered to 4.2°K from room temperature. / Science, Faculty of / Physics and Astronomy, Department of / Graduate