2-Indolylphosphines are unique ligands which have the capability for further phosphine modification by introducing substituents on an indolyl nitrogen centre. Substituents can vary in electronics, sterics, chirality, and can contain amino or phosphino groups which result in a multidentate (P,N)- or (P,P)-2-indolylphosphine. X-ray crystallography was used predominantly to examine and analyze the structural features of 2-indolyphosphines and their metal complexes. While the cone angles could not be determined crystallographically, the sum of the <CPC bond angles provided some information on the steric crowding around a phosphorus atom in selected 2-indolylphosphines. The symmetric tris-2-(3-methylindolyl)phosphine demonstrated anion binding ability through its three indolyl NH sites. Titrations to a series of selected anions were carried out; it was determined that tris-2-(3-methylindolyl)phosphine binds to these selected anions in a 1 : 1 receptor to anion binding ratio. Crystal structures of the fluoride and acetate complexes confirm the binding stoichiometry, and demonstrate the cooperative interaction of all three indolyl NH sites with the anion guest. Synthetic routes to new anion receptors with three or two indolyl NH donors were explored. The second type yielded a molecular cleft that was used in anion binding studies. The net basicity of a 2-indolylphosphine was determined through formation of a Ni(CO)3L complex. Net basicity can be tuned by changing the substituents on phosphorus or on an indolyl nitrogen centre. The [Cu(tris-2-(3-methylindolyl)phosphine)(phenanthroline)]BF4 complex is a discrete ion pair complex, exhibiting coordination chemistry at the phosphorus centre of the phosphine, while simultaneously hydrogen bonding through the indolyl NH sites to the BF4- anion. Complexes of the type [Pd(L)Cl(mu-Cl)]2 were analyzed by crystallography and the effect of net basicity on Pd-P bond length examined. The solid-state structures of (P,N)- and (P,P)-2-indolylphosphines were evaluated. In general, the sum of the <CPC bond angles increased from the parent unfunctionalized 2-indolylphosphine. The metal complexes of (P,N)- and (P,P)-2-indolylphosphines were assessed by crystallography to find possible trends of trans-influence. Lastly, a tetradentate tripodal ligand was synthesized by furnishing diphenylphosphino substituents on the indolyl nitrogen centres of tris-2-(3-methylindolyl)phosphine. The coordination of the tetradentate tripodal ligand to Pt(II) or Rh(I) resulted in five-coordinate trigonal bipyramidal complexes.

Excitations of the valence electrons in the high-temperature superconducting cuprate La2−xSrxCuO4 were measured by Resonant Inelastic X-ray Scattering (RIXS). Several types of electronic excitations resonant at the Cu 1s →4p transition were studied over a wide range of dopings 0<x<0.35. A 500 meV excitation was observed at a reduced momentum transfer q=(π 0) corresponding to the zone boundary, whose temperature and doping dependence was the same as the two-magnon Raman scattering mode. The momentum dependence of this 2-magnon excitation agrees with recent theoretical calculations. Momentum resolved measurements of the x=0 sample revealed a broad range of excitations above and below the main charge transfer peak, and their dispersions were measured across the Brillouin zone. These include a dispersionless ∼1.8 eV peak, which is either a local crystal field (d-d excitation) or dipole-forbidden charge transfer excitation, and a dispersive 2.2 eV peak identified as a Zhang-Ng type charge-transfer exciton. The 2.2 eV peak was less dispersive than predicted from the theoretical models, due to electron-phonon coupling, as illustrated by the temperature dependent shift in the peak position. With increased hole doping, the RIXS spectral weight transfers from higher to lower energies, analogous to earlier optical conductivity studies. At the finite momentum of q=(π 0), however, the changes are most systematic: an isosbestic point was observed at 2.2 eV where the spectra of all dopings cross, and spectral weight is transferred from high to low energies, with near-linear dependence on x, in a manner suggesting that the integrated RIXS intensity is preserved. The intensity and energy variations of the spectral peaks, as well as the isosbestic point and possible sum rule, could be explained qualitatively by a rigid three-band model which includes the non-bonding oxygen, upper Hubbard, and Zhang-Rice singlet bands. The estimated properties of the bands, such as width and energy separation, are in reasonably quantitative agreement with current theoretical models and angle-resolved photoemission measurements. Moreover, anomalies in the doping dependence are similar to those observed in other types of spectroscopies. These results underscore the relevance of the RIXS method in understanding the electronic behavior of the Lanthanum cuprates.

Modeling and simulation results for two types of 150 μm height air suspended inductors proposed for LIGA fabrication are presented. The inductor substrates used model the TSMC 0.18 μm CMOS/BiCMOS substrates. The RF performance between the suspended structure and the unsuspended counterpart are compared and the advantage of the suspended structures is explored. The potential of LIGA for fabricating high suspended inductors with good performance and for combining these with CMOS/BiCMOS is demonstrated.

2-Indolylphosphines are unique ligands which have the capability for further phosphine modification by introducing substituents on an indolyl nitrogen centre. Substituents can vary in electronics, sterics, chirality, and can contain amino or phosphino groups which result in a multidentate (P,N)- or (P,P)-2-indolylphosphine. X-ray crystallography was used predominantly to examine and analyze the structural features of 2-indolyphosphines and their metal complexes. While the cone angles could not be determined crystallographically, the sum of the <CPC bond angles provided some information on the steric crowding around a phosphorus atom in selected 2-indolylphosphines. The symmetric tris-2-(3-methylindolyl)phosphine demonstrated anion binding ability through its three indolyl NH sites. Titrations to a series of selected anions were carried out; it was determined that tris-2-(3-methylindolyl)phosphine binds to these selected anions in a 1 : 1 receptor to anion binding ratio. Crystal structures of the fluoride and acetate complexes confirm the binding stoichiometry, and demonstrate the cooperative interaction of all three indolyl NH sites with the anion guest. Synthetic routes to new anion receptors with three or two indolyl NH donors were explored. The second type yielded a molecular cleft that was used in anion binding studies. The net basicity of a 2-indolylphosphine was determined through formation of a Ni(CO)3L complex. Net basicity can be tuned by changing the substituents on phosphorus or on an indolyl nitrogen centre. The [Cu(tris-2-(3-methylindolyl)phosphine)(phenanthroline)]BF4 complex is a discrete ion pair complex, exhibiting coordination chemistry at the phosphorus centre of the phosphine, while simultaneously hydrogen bonding through the indolyl NH sites to the BF4- anion. Complexes of the type [Pd(L)Cl(mu-Cl)]2 were analyzed by crystallography and the effect of net basicity on Pd-P bond length examined. The solid-state structures of (P,N)- and (P,P)-2-indolylphosphines were evaluated. In general, the sum of the <CPC bond angles increased from the parent unfunctionalized 2-indolylphosphine. The metal complexes of (P,N)- and (P,P)-2-indolylphosphines were assessed by crystallography to find possible trends of trans-influence. Lastly, a tetradentate tripodal ligand was synthesized by furnishing diphenylphosphino substituents on the indolyl nitrogen centres of tris-2-(3-methylindolyl)phosphine. The coordination of the tetradentate tripodal ligand to Pt(II) or Rh(I) resulted in five-coordinate trigonal bipyramidal complexes.

Excitations of the valence electrons in the high-temperature superconducting cuprate La2−xSrxCuO4 were measured by Resonant Inelastic X-ray Scattering (RIXS). Several types of electronic excitations resonant at the Cu 1s →4p transition were studied over a wide range of dopings 0<x<0.35. A 500 meV excitation was observed at a reduced momentum transfer q=(π 0) corresponding to the zone boundary, whose temperature and doping dependence was the same as the two-magnon Raman scattering mode. The momentum dependence of this 2-magnon excitation agrees with recent theoretical calculations. Momentum resolved measurements of the x=0 sample revealed a broad range of excitations above and below the main charge transfer peak, and their dispersions were measured across the Brillouin zone. These include a dispersionless ∼1.8 eV peak, which is either a local crystal field (d-d excitation) or dipole-forbidden charge transfer excitation, and a dispersive 2.2 eV peak identified as a Zhang-Ng type charge-transfer exciton. The 2.2 eV peak was less dispersive than predicted from the theoretical models, due to electron-phonon coupling, as illustrated by the temperature dependent shift in the peak position. With increased hole doping, the RIXS spectral weight transfers from higher to lower energies, analogous to earlier optical conductivity studies. At the finite momentum of q=(π 0), however, the changes are most systematic: an isosbestic point was observed at 2.2 eV where the spectra of all dopings cross, and spectral weight is transferred from high to low energies, with near-linear dependence on x, in a manner suggesting that the integrated RIXS intensity is preserved. The intensity and energy variations of the spectral peaks, as well as the isosbestic point and possible sum rule, could be explained qualitatively by a rigid three-band model which includes the non-bonding oxygen, upper Hubbard, and Zhang-Rice singlet bands. The estimated properties of the bands, such as width and energy separation, are in reasonably quantitative agreement with current theoretical models and angle-resolved photoemission measurements. Moreover, anomalies in the doping dependence are similar to those observed in other types of spectroscopies. These results underscore the relevance of the RIXS method in understanding the electronic behavior of the Lanthanum cuprates.

Modeling and simulation results for two types of 150 μm height air suspended inductors proposed for LIGA fabrication are presented. The inductor substrates used model the TSMC 0.18 μm CMOS/BiCMOS substrates. The RF performance between the suspended structure and the unsuspended counterpart are compared and the advantage of the suspended structures is explored. The potential of LIGA for fabricating high suspended inductors with good performance and for combining these with CMOS/BiCMOS is demonstrated.

This paper briefly describes the theory and methods of x-ray residual stress measurements. Residual stresses can be defined as the stresses which remain in a material in the absence of any external forces. There are many stress determination methods. Some of those methods are destructive and some are nondestructive. X-ray residual stress measurement is considered as a nondestructive method. X-ray diffraction together with the other diffraction techniques of residual stress measurement uses the distance between crystallographic planes as a strain gage. The deformations cause changes in the spacing of the lattice planes from their stress free value to a new value that corresponds to the magnitude of the residual stress. Because of Poisson’s ratio effect, if a tensile stress is applied, the lattice spacing will increase for planes perpendicular to the stress direction, and decrease for planes parallel to the stress direction. This new spacing will be the same in any similarly oriented planes, with respect to the applied stress. Therefore the method can only be applied to crystalline, polycrystalline and semi-crystalline materials. The diffraction angle, 2&#952;, is measured experimentally and then the lattice spacing is calculated from the diffraction angle, and the known x-ray wavelength using Bragg's Law. Once the d-spacing values are known, they can be plotted versus 2 sin &#968;, ( &#968; is the tilt angle). In this paper, stress measurement of the samples that exhibit a linear behavior as in the case of a homogenous isotropic sample in a biaxial stress state is included. The plot of d vs. 2 sin &#968; is a straight line which slope is proportional to stress. On the other hand, the second set of samples showed oscillatory d vs. 2 sin &#968; behavior. The oscillatory behavior indicates the presence of inhomogeneous stress distribution. In this case the xray elastic constants must be used instead of E and &#957; values. These constants can be obtained from the literature for a given material and reflection combination. It is also possible to obtain these values experimentally. Calculation of the residual stresses for these samples is beyond the scope of this paper and will not be discussed here.

published_or_final_version / Physiology / Master / Master of Philosophy

Supersoft and quasisoft X-ray sources are collectively known as Very Soft X-ray Sources (VSSs) characterized by their considerably lower effective temperatures than normal X-ray emitting objects and the lack of significant emission above 1 keV, with measured temperatures ranging from about tens to less than about 300 eV, respectively. They are defined observationally and believed to be associated with a wide variety of astrophysical systems such as white dwarfs, neutron stars, and black holes. VSSs have been identified in our own Galaxy, the Magellanic Clouds, and other external galaxies. Due to the vicinity of the Magellanic Clouds and the low associated absorption of soft X-ray photons, they are unique in the studies of VSSs. However, no attempt has been made to search for VSSs and investigate the source population in the Magellanic Clouds using all the available archival data. A systematic survey of VSSs in the Magellanic Clouds was therefore performed using data from both XMM-Newton and Chandra. VSSs were identified by selection algorithim based on X-ray hardness ratio after the background galaxies and foreground stars were filtered. A total of 47 new supersoft and 75 new quasisoft candidates were identified. Six of them were strong enough for spectral analysis with derived temperatures of 15 – 250 eV and luminosities of of 3.5 ×?10?^34– 5.4 ×?10?^36 erg s^(-1). The softest and brightest candidate represents a promising supersoft candidate with a possible UV counterpart identified with XMM-Newton Optical Monitor having an estimated UV luminosity of ~2.7 ×?10?^35 erg s^(-1). The large dataset also allows the long-term studies of some of the previously identified supersoft X-ray sources. Through the comprehensive survey with multi-epoch data, an X-ray/UV stellar flare was discovered and its analysis is also reported. / published_or_final_version / Physics / Master / Master of Philosophy

X-ray crystallography is a powerful method in determining the structure of both small molecules and macromolecules and is now routinely applied in many scientific fields. However, to apply this method, there is an unavoidable problem to tackle: the Phase Problem, which arises because the phases of a scattered x-ray cannot be measured in diffraction experiment and the original structure cannot be retrieved only with the measurable amplitudes. This thesis presents two approaches in the development of macromolecular phasing methods. One approach presented here utilizes molecular envelope of NMR structures for molecular replacement (MR) phasing with the program FSEARCH at low resolution (about 6 Å). X-ray crystallography and NMR are complementary tools in structural biology. However, it is often difficult to use NMR structures as search models in MR to phase crystallographic data. For this purpose, in our study, several targets with both crystallographic and NMR structures available have been tested. The test protocol involves four steps: (1) Model preparation, NMR structures were processed into averaged polyalanine model, and centroid NMR models have also been tested; (2) Six-dimensional low resolution search were carried out by FSEARCH to find the best match between observed and calculated structure factors; (3) Apply the solution (4) Model building and refinement. In our tests, FSEARCH was able to find the correct translation and orientation of the search model in the crystallographic unit cell, while conventional MR procedures were unsuccessful. The other approach presented in this thesis is protein complex structure completion using IPCAS (Iterative Protein Crystal structure Automatic Solution). Protein complexes have been concerned as essential components in almost every cellular process. X-ray crystallography method is quite useful in studying the nature of protein complexes. In this study, we demonstrated a protein complex completion procedure from a partial molecular replacement (MR) solution using IPCAS. IPCAS is a direct-method aided dual-space iterative phasing and model-building procedure. The test cases were carefully selected from a practical perspective and IPCAS could build the whole complex from one or less than one subunit once molecular replacement method could give a partial solution. Before delivering to IPCAS, MR solution model examination and improvement might be necessary. The IPCAS iteration procedure involves (1) real-space model building and refinement; (2) direct-method aided reciprocal-space phase refinement; and (3) phase improvement through density modification. In our tests, IPCAS is able to extend the full length complex from a less than 30% starting model while conventional model building procedure were unsuccessful. / published_or_final_version / Physiology / Doctoral / Doctor of Philosophy