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Raman and/or infrared (IR) bandshape analysis to probe molecular dynamics in liquids has become a rapidly expanding field of study in recent years. Determination of spinning and tumbling diffusion constants, Dι and D⊥, which characterize the reorientation of symmetric-top moleclues has been successfully studied in a number of D6H and D3H molecules. For molecules of CV3 symmetry, however, previous attempts to extract spinning diffusion constants from Raman doubly degenerate vibrations (E mode) have proved unsuccessful. Presented here is a new methodology which resolves the problems encountered by former researchers through calculation of Dι utilizing the narrower Lorentzian component of E vibrations.

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One of the main challenges in experimentally identifying a quantum spin liquid (QSL) state is in understanding the influence of disorder. Chemical and structural imperfections exist in many promising QSL candidate materials, and can lead to a spatially inhomogeneous behaviour that obfuscates the interpretation of sample-averaged measurements. This issue highlights the importance of nuclear magnetic resonance (NMR) which can locally probe the intrinsic spin susceptibility χspin (separate from defect contributions) and low-energy spin fluctuations via the Knight shift K and nuclear spin-lattice relaxation rate 1/T1, respectively. The value of 1/T1 is typically ascertained by fitting the net nuclear magnetization M(tD) with an appropriate decay function. However, the M(tD) measured at a given frequency has contributions from many nuclei, which in a disordered material, can exhibit a broad distribution of 1/T1. Analogous to how variations in local χspin are reflected in the distribution of Knight shifts which make up the inhomogeneously broadened NMR lineshape, the distribution of 1/T1 that make up a single M(tD) curve can represent multiple environments whose local magnetic ground states are qualitatively distinct. We developed a program which computes the inverse Laplace transform (ILT) of our measured M(tD) data, in order to deduce a probability density function P(1/T1) representing the 1/T1 distribution. Our ILT algorithm primarily employs Tikhonov regularization, which iv limits the instability of numerically inverting data with finite noise. This 1/T1 analysis method offers significant advantages over the traditional method of fitting M(tD) against a phenonmenological stretched exponential function, which provides only a crude approximation of the spatial average of the 1/T1 distribution. In contrast, our approach of calculating P(1/T1) using ILT can delineate the behavior of multiple distinct 1/T1 components, and hence preserve vital information on the position-by-position distribution of local spin dynamics. In this thesis, we report on our 7Li NMR measurements of the Kitaev honeycomb iridate Ag3LiIr2O6, our 63Cu nuclear quadrupole resonance (NQR) measurements on the kagome Heisenberg antiferromagnets ZnCu3(OD)6Cl2 (herbertsmithite) and ZnCu3(OD)6FBr (Zn-barlowite), and further measurements of ZnCu3(OD)6FBr with 19F NMR. Using ILT, we provide crucial insight into both the intrinsic and disorder-induced low-energy spin excitations of these materials. Firstly, we elucidate the effect of stacking faults and unwanted Ag inclusion by comparing the 7Li NMR lineshape and P(1/T1Li) of Ag3LiIr2O6 samples with varying levels of disorder. Next, we observe in P(1/T1Cu) a fraction of spin singlets with spatially inhomogeneous energy gaps emerging below ∼30 K within the kagome planes of ZnCu3(OD)6Cl2 and ZnCu3(OD)6FBr. Finally, we develop a novel method using ILT to obtain the two-dimensional correlation map between 19K and 1/T1F at the 19F sites of ZnCu3(OD)6FBr, and evidence the existence of spin-polarized domains emerging near interlayer Cu2+ defects. / Thesis / Doctor of Science (PhD) / A quantum spin liquid (QSL) is an exotic state of matter whose magnetism fundamentally differs from those of ordinary materials. At temperatures near absolute zero, the electron spins which make up an ordinary magnet generally freeze in place, whereas in a QSL, they form a highly-entangled quantum superposition. A theoretically attainable QSL state was famously proposed in 1973 by Philip W. Anderson. Since then, several candidate materials have been discovered, and research on QSLs became a major focus in the field of condensed matter physics. The realization of a QSL is predicted to have applications in quantum computing (by hosting more robust quantum bits), and can help us understand the physics of other quantum materials, such as high-temperature superconductors. In this thesis, we report our experimental findings on the QSL candidates Herbertsmithite, Zn-barlowite, and Ag3LiIr2O6, where we use nuclear magnetic resonance (NMR) spectroscopy to probe the behaviour of their spins. Hindering past attempts to study these materials is the ever-present influence of disorder, such as chemical and structural imperfections. To combat this, we developed a novel technique for acquiring and analyzing NMR data, known as inverse Laplace transform (ILT) 1/T1 analysis, and used it to make unprecedented discoveries about the heterogeneous physics of these disordered materials.

The contact angle defined by Young's equation depends on the ratio between solid and liquid surface energies. Young's contact angle is constant for a given system, and cannot explain the stability of fluid droplets in capillary tubes. Within this framework, large variations in contact angle and explained aassuming surface roughness, heterogeneity or contamination. This research explores the static and dynamic behavior of fluid droplets within capillary tubes and the variations in contact angle among interacting menisci. Various cases are considered including wetting and non-wetting gluids, droplets in inclined capillary tubes or subjected to a pressure difference, within one-dimensional and three-dimensional capillary systems, and under static or dynamic conditions (either harmonic fluid pressure or tube oscillation). The research approach is based on complementary analytical modeling (total energy formulation) and experimental techniques (microscopic observations). The evolution of meniscus curvatures and droplet displacements are studied in all cases. Analytical and experimental results show that droplets can be stable within capillary tubes even under the influence of an external force, the resulting contact angles are not constant, and bariations from Young's contact angle aare extensively justified as menisci interaction. Menisci introduce stiffness, therefore two immiscible Newtonian fluids behave as a Maxwellian fluid, and droplets can exhibit resonance or relaxation spectral features.

This thesis involves the synthesis of two main classes of triaminocyclopropenium (tac) Ionic Liquids (ILs) (i) Amino Acid Ionic Liquids (AAILs) and (ii) reduced-symmetry cations. [C₃(NEt₂)₂(NRR’)]X (X = TFSA and MeSO₄) were prepared, whereby NHR is derived from amino acids. Optically pure AAILs, [E₄AminoAcid]X (X = TFSA and MeSO₄) were obtained as a mixture of the IL and its zwitterion. The ratios of these mixtures were determined by pH titration and microanalysis. The AAILs specific rotations and pKa values were determined. AAILs can be used for chiral discrimination and form diasterreomeric salts with the entioenriched sodium salt of Mosher’s acid. The AAILs were also successfully used as a solvent and/or catalyst in an aldol reaction and a Diels-Alder reaction. The low-molecular weight series, [C₃(NMe₂)₂(NRR’)]X and [C₃(NMe₂)₂(NR’2)]X was synthesized and characterized: protic ILs NRR’, where R = ethyl, propyl, allyl, butyl, - CH2CH2OCH₃ and pentyl, R’ = H and X = TFSA: and aprotic ILs NRR’, where R = Me, R’ = ethyl, allyl, propyl, butyl, -CH2CH2OCH₃ and hexyl and X = TFSA and DCA. ILs with C2v symmetry [C₃(NEt₂)₂(NH2)]X (X = TFSA and MeSO₄), [C₃(NEt₂)₂(NBu2)]I, [C₃(NEt₂)₂(NHex₂)]I and [C₃(NEt₂)₂(NHex₂)]OTf were also synthesized and characterized. The C₃h cations, [C₃(NMeR)₃]X (R = ethyl, allyl, -CH2CH2OCH₃ and phenyl, X = TFSA and DCA) were successfully prepared as well. The D₃h cation salts [C₃(NEt₂)₃]X (X = MeC6H4SO₃, OTf, I and F5C6O) and [C₃(NBu2)₃]X (X = B(CN)4 and FAP) were also prepared. The tac-based ILs [C₃(NEt₂)₃]+ and [C₃(NBu2)₃]+ were also complexed with metal halides - - 2- 2- forming salts with FeCl₄ , SnCl₃ , CuCl₄ and ZnCl₄ . Reaction of pentachlorocyclopropane (C₃Cl5H) with BuNH2 gave the open ring allylium product [H2C₃(NBuH)4]2+. This was characterized as Cl- and TFSA- salt. During the synthesis of [C₃(NMe₂)₃]Cl, the open ring cation [HC₃(NMe₂)4]+ was also isolated and was characterized as the TFSA- salt. XX Abstract The TGA, DSC, density, viscosity, conductivity, and molar conductivity properties for the ILs were measured where possible. The viscosity and conductivity data was fitted for the Arrhenius and Vogel-Fulcher Tamman equations. The entire tac-based ILs lie below the KCl ideal line in Walden plot. A fragility plot was obtained by fitting the viscosity data and all the tac-based ILs were fragile. The crystal structures of [C₃(NPhH)₃]TFSA, [C₃(NEt₂)₃]FeCl₄ and [HC₃(NMe₂)4]Cl.2CH₃Cl were determined.

abstract: The field of Ionic Liquid (IL) research has received considerable attention during the past decade. Unique physicochemical properties of these low melting salts have made them very promising for applications in a many areas of science and technology such as electrolyte research, green chemistry and electrodeposition. One of the most important parameters dictating their physicochemical behavior is the basicity of their anion. Using four sets of Protic Ionic Liquids (PILs) and spectroscopic characterization of them, a qualitative order for anion basicity of ILs is obtained. Protic Ionic Liquids are made by proton transfer form a Brønsted acid to a base. The extent of this transfer is determined by the free energy change of the proton transfer process. For the cases with large enough free energy change during the process, the result is a fully ionic material whereas if the proton transfer is not complete, a mixture of ions, neutral molecules and aggregates is resulted. NMR and IR spectroscopies along with electrochemical and mechanical characterization of four sets of PILs are used to study the degree of ionicity. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2016

The flow properties of two types of operating and clean coolants (A and B) were measured, both used in metalworking. Four samples of both operating liquids were sampled from the process monthly (from the beginning to the end of its use). All liquids were measured at 25 °C with an oil emulsion content of 4%. In addition, flow curves of pure cooling emulsions with concentration of coolant 2, 4, 6 and 8% were measured at 30, 35, 40, 45 and 50 °C. Rheological measurement was performed at geometry of concentric cylinders. Microbial activity and content of additives (Thermogravimetry) was determined in operating liquid A. Both operating liquids exhibited non-Newtonian behavior. Viscosity increased with the shear rate (10–100 s-1) and impurity level. Although the amount of impurity was approximately the same in both liquids, viscosity varied. For pure liquids, the viscosity increased with increasing concentration and decreased with increasing temperature, except for liquid A with concentration of coolants 6 and 8%, which, depending on the temperature, exhibited both shear thinning, shear thickening and Newtonian behavior. The results shown that impurity level of operating liquids has only minor effect on viscosity and flow properties, but it had an effect on cooling effect. Impurities diluted operating liquids, partial decomposition of the oil component may occur, but in particular, microbial activity causes skin problems of staff. Recommended is to introduce a specific control test for the presence of bacteria.

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