Following an introoduction on calixarene chemistry and their metal-ion complexes including some of their applications, the aims of the work are described. Thus, the first part of this thesis concerns the detemination of the standard enthalpies of solution, sH°, of new lithium and sodiimi 1:1 electrolytes based on eth p=tert-butycalix[4]arene tetraethanoate containing various anions in acetonitrile at 298.15 K. Using these data in conjunction with previously reported sH° values for the free metal-ion salts and the ligand and standard enthalpies of complexation, cH°H° of allcali-metal cations (Li+ and Na+) and the calix[4]arene ester in the same solvent, standard enthalpies of coordination, coordH° referred to the process in which the reactants and the product are in the solid stated were calculated. The anion effect on the coordination process was determined. The second part of this thesis is related to an investigation on the solution properties of pyridinocalix[4]arenes and their metal-ion complexes. Transfer Gibbs energies of geometrical isomers of pyridinocalix[4]arenes from acetonitrile to various solvents reflect that these ligands undergo selective solvation in the various solvents but these cannot be correlated with any single solvent property. The complexing ability of 5,11,17,23 - tetra - tert - butyl[25,26,27,28 - tetrakis (2-pyridyhnethyl) oxy]- calix[4]arene for metal cations was investigated by a variety of techniques. Thus 1H NMR studies were performed to obtain information about the active sites of the ligand in its interaction with metal cations. Conductance measurements were used to establish the composition of the metal-ion complexes in dipolar aprotic media. Potentiometric and calorimetric measurements were performed to derive the thermodynamics associated with the complexation process in acetonitrile and benzonitrile. Based on stability constant data, two metal-ion complexes were isolated. The crystal structure of the sodium and acetonitrile complex of 5,11,17,23- tetra- tert- butyl[25,26,27,28 - tetrakis (2-pyiidylmethyl)oxy] calix[4] arene solved by X-ray diffraction studies shows three different complexes in the lattice, two sited on a fourfold axis and a third one on a twofold axis where all ligands exhibit a 'cone' conformation and the sodium ion is encapsulated in their hydrophilic pockets with their hydrophobic cavities filled with an acetonitrile molecule. The crystal structure of the 1:1 monoacetonitrile and silver complex of the 2-pyridyl derivative with the perchlorate ion as the counter ion shows the macrocycle sited on a fourfold symmetry axis. The presence of acetonitrile in the hydrophobic cavity of the ligand is also found. The silver cation is encapsulated in the hydrophilic cavity through the ethereal oxygens and the pyridinic nitrogens. Conclusions and suggestions for furthur research in this area are given.

A detailed investigation of ion crystals produced by laser and sympathetic cooling in a linear RF trap has been conducted. The laser cooling methods were examined and applied to the trapped ^24Mg^(positive) ions. The crystals produced by the laser cooling were studied, including the dependence on RF voltage, end cap DC voltage, laser power and laser frequency. By manipulating the different RF voltages and endcap DC voltages, the structure phase transition of the ion crystals was observed. In addition, the sympathetic cooling of different ion species with the laser cooled 24Mg^(positive) was carried out. In this process, the mixed Mg^(positive) and He^(positive) crystals were created andidentified, and mixed Mg^(positive) and H2^(positive) crystals were produced. The effect of an unwanted chemical reaction of Mg^(positive) and H2 was observed and minimized. After sympathetic cooling of light ion species, the sympathetic cooling of heavy molecular ions such as fullerene ions was also carried out. The efficiencies and final temperature in both cases are very different. Theoretically to interpret the results, molecular dynamics simulations of the laser cooling and sympathetic cooling were implemented. And the simulations were compared with the experimental results. In the process of carrying out this research, the optics were rebuilt to provide reliable UV sources for the photoionization and laser cooling of Mg ions. The imaging system was reconfigured to take the images of ion crystals. New elements were added tin the ion trap to improve the ability to manipulate ions.

<p> A theory of spin waves for the spin structures found in the rare earth metals of hcp crystal structure is described. The theory is developed for the conical spiral spin structure which contains the planar spiral, the nonplanar ferromagnet and the planar ferromagnet as special cases. Included in the Hamiltonian are isotropic and anisotropic exchange interactions, single-ion crystal field terms, and magnetoelastic terms, both of the single-ion type and the two-ion type. Equations of motion for the spin operators are linearized with the help of the random phase approximation which makes it possible to express some spin-wave interaction effects in terms of powers of the reduced magnetization. Expressions for the spin-wave energies are given for the four structures under consideration.</p> / Thesis / Master of Science (MSc)

In this thesis we present a computational study of “ion crystals”, the interesting patterns in which ions arrange themselves in ion traps such as Paul and Penning traps. In ion crystals the ions are in equilibrium due to the balance of the repulsive forces between the ions and the overall tendency of the ion trap to pull ions towards the trap centre. We have carried out a detailed investigation of ion crystals in Paul traps by solving their equations of motion numerically. We also propose a model called the spring–mass model to explain the formation of ion crystals. This model is far more efficient than direct numerical simulation for predicting ion crystal structures. Finally, we demonstrate that there is a power law relating distance of an ion from the trap centre in ion crystals to the applied RF voltage amplitude.