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1
Drake, Jeremy J. „High resolution stellar spectroscopy“. Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236268.
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2
Anderson, Darlene. „Studies in high resolution spectroscopy“. Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26766.
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The ground state microwave spectra of hypochlorous acid (HOCl), carbonylchlorofluoride (FClCO), and N-chlorodifluoromethylenimine (CF₂NCI), have been measured from 8 — 80 GHz and analyzed. The 8[sup 2/sub0] vibrational band of aminoborane (NH₂BH₂) near 1223 cm⁻¹ has been recorded at a resolution of 0.004 cm⁻¹ and analyzed.
HOCl: Rotational constants and quartic centrifugal distortion constants were obtained for the following four isotopic species of hypochlorous acid: D¹⁶O³⁵Cl, D¹⁶O³⁷Cl, H¹⁸O³⁵Cl and H¹⁸O³⁷Cl. The centrifugal distortion constants were combined with vibrational wavenumbers from the literature to determine a valence harmonic force field which was used to calculate an average structure and an estimated equilibrium structure. Effective and full substitution structures have also been evaluated.
FClCO: An extensive set of transitions, to high J and K has been measured
for the two most abundant species, F³⁵CI¹²CO and F³⁷CI¹²CO, which allowed
accurate values for the rotational constants, centrifugal distortion constants and
the chlorine nuclear quadrupole coupling constants to be evaluated for each. An
estimate of the three rotational constants for F³⁵CI¹³CO was made from the four transitions measured, as it exists in natural abundance. Harmonic force constants were produced from ab initio calculations and were used in the determination of its harmonic force field. Effective and average structural parameters have been determined.
CF₂NCI: Rotational constants and quartic centrifugal distortion constants have
been obtained for the two isotopic species CF₂N³⁵CI and CF₂N³⁷CI. The
nuclear quadrupole coupling constants of both ¹⁴N and CI have been evaluated. A partial harmonic force field has been determined from the available data. Both effective and average structural parameters have been obtained and indicate that the structure of CF₂NCI is a hybrid of those of CF₂NF and CCl₂NCl. The nuclear quadrupole coupling constants have provided information about the bonding in the molecule.
NH₂BH₂: Rotational constants and centrifugal distortion constants of the upper
vibrational state 2v₈ have been determined and have confirmed the assignment
of the band. The least squares refinement of the constants has shown an
increasing poorness of fit to the higher K[sub a] transitions which has suggested the
possiblity of Coriolis type perturbations.Science, Faculty of
Chemistry, Department of
Graduate
3
Woodward, D. R. „High resolution spectroscopy of transient species“. Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376972.
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4
Hayman, G. D. „High resolution spectroscopy of molecular beams“. Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371513.
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5
Enos, C. S. „Applications of high-resolution translational spectroscopy“. Thesis, Swansea University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636906.
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In 1927, E.P. Wigner proposed that in the event of weak spin-orbit coupling the only spectroscopic processes likely to occur were those for which the total electron spin angular momentum was conserved, namely ΔS = 0. This later became known as the Wigner Spin Conservation Rule. Its implications for radiative processes have been extensively investigated and it is now known that they adhere closely to the ΔS = 0 selection rule. In contrast, the application of the spin rule to binary collisional processes has been the subject of a small number of studies from which only tentative conclusions could be drawn as to its validity. To redress this imbalance, a systematic investigation was undertaken by the author for ion (keV)-particle (thermal) collisions, the results of which are presented in this thesis. In total, 164 reaction channels were identified of which the overwhelming majority (158) were found to be spin conservative. Furthermore, a modified version of the ΔS = 0 selection rule is proposed which states that if one collision partner undergoes a transition involving a multiplicity change a simultaneous transition in the other partner must conform to the selection rule ΔS = 0 or 1 with the proviso that singlet-singlet transitions are forbidden. During a charge stripping investigation of 4keV B^+,C^+ and Ar^+ ions, several features observed in the spectra using non-singlet target particles such as O_2 and NO, were not present when singlet target particles such as N_2 and Ne were used. To explain these discrepancies, a novel pseudo two step mechanism is proposed in which the ion undergoes a rearrangement stage prior to explusion of the electron. Metastable ions substantially influence collisional processes and to facilitate the former investigations, the fractional metastable content of six atomic ion beams (B^+, C^+, N^+, O^+, F^+ and Cl^+) formed by Electron Ionization are quantified.
6
梁韻詩 und Wan-sze Leung. „High resolution spectroscopy of free radicals“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31237319.
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7
Xia, Ye, und 夏晔. „High resolution spectroscopy of scandium monohalides“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49617886.
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This thesis reports the study of the molecular and electronic structure of scandium monohalides using the technique of laser ablation/reaction with supersonic free jet expansion used for producing the target molecules and laser induced fluorescence (LIF) spectroscopy for recording their electronic transition spectrum. The scandium diatomic molecules studied in this work were scandium monoiodide (ScI) and scandium monobromide (ScBr), which were produced by the reaction of Sc atoms with 2% CH3I and 2% C2H5Br gases seeded in Ar carrier gas, respectively. The LIF spectrum of the electronic transition of ScI and ScBr were recorded in the visible and near infrared spectral region between 613 and 854 nm. The analysis of the high resolution electronic spectra of ScI and ScBr yielded molecular constants and information of electronic structures. For all the transition bands observed, rotationally-resolved transition lines were fit to a theoretical model to retrieve molecular constants for both upper and lower electronic states.
For the ScI molecule, seven vibrational bands of the D1П –X^1 Σ^+ system were recorded and analyzed. Accurate molecular constants for the v = 0 – 2 levels of the D^1П state and the v = 0 – 3 levels of the X^1 Σ^+ state were obtained. The equilibrium bond lengths, re (Å), for the electronic states of ScI were determined as follows:
ScI X^1 Σ^+ D^1П
r_e(Å) 2.6078 2.7146
For the ScBr molecule, three electronic transition systems were recorded and analyzed, which include six vibrational bands of the C^1 Σ^+– X^1 Σ^+ system, seven vibrational bands of the e^3Δ–a^3Δsystem and two vibrational bands of the d3Φ – a3Δ system. Rotationally resolved transition lines of both Sc79Br and Sc81Br isotopes were observed and analyzed. Least-squares fitting of the measured line positions yielded accurate molecular constants for the v = 0 – 2 levels of the X^1 Σ^+ state, the v = 0 – 3 levels of the C^1 Σ^+ state, the v = 0 and 1 levels of the d3Φ state and the v = 0 – 2 levels of both e3Δ and a3Δ states, respectively. The equilibrium bond lengths, re (Å), determined for electronic states of ScBr are given as follows:
ScBr X^1 Σ^+ a^3Δ C^1 Σ^+
r_e(Å) 2.3806 2.4767 2.4776
A molecular orbital (MO) energy level diagram has been used to examine the electronic configurations giving rise to the different observed electronic states of ScI and ScBr. An attempt has been made to put the MOs of all the scandium monohalides under a single picture. A comparison of the molecular constants for the different electronic states of scandium monohalides indicates a weakening of the chemical bonding between the scandium atom and the halogen atoms down the group.published_or_final_version
Chemistry
Doctoral
Doctor of Philosophy
8
Leung, Wan-sze. „High resolution spectroscopy of free radicals /“. Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19737610.
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9
Phillips, Alexander John. „High resolution and sensitivity gas phase spectroscopy“. Thesis, Queen Mary, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267656.
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10
Walsh, M. A. „High resolution spectroscopy of weakley bound complexes“. Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382655.
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11
Setio, Utomo A. B. „High resolution spectroscopy using tunable diode lasers“. Thesis, Swansea University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638795.
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It has been demonstrated in this work that commercial hollow cathode discharge lamps can be used for optogalvanic, absorption, fluorescence and polarisation absorption techniques by sending the beams in counter propagating and perpendicular direction to the cylinder axis of the discharge lamp, in-between its anode and cathode. Experiments have been performed using a number of single mode diode lasers to investigate selected lines of argon (~772 nm), rubidium (~780 nm) and lithium (~670 nm). To control the hollow cathode discharge lamp, a special, low-noise DC power supply was built in-house. It is able to produce output voltages of up to 400 Volts at up to 50 mA current; the current is stabilised by an active current sink. The unit also incorporated an AC coupled low-noise amplifier to detect the optogalvanic signal when excitation resonance takes place in the discharge lamp. In optogalvanic (OG) spectroscopy, transitions in rubidium, lithium and argon were investigated. In the spectrum of rubidium, the intensities of the D_2-line components roughly mirror the isotopic abundances (72.15% for ^85Rb nd 27.85% for ^87Rb) and some of the hyperfine structure and isotope shifts are resolved. Only the fine structure splitting between D_1 and D_2 of the two isotopes ^6Li and ^7Li (isotope abundances of 7.4% and 92.6% respectively) are well resolved by our diode laser. The line structure shows a three-component feature; two of the components are rather strong while the third (at the longest wavelength; 2^2S_1/2 - 2^2P_1/2 transition) is very weak which is hardly detectable in the spectrum. This third, weak component due to ^6Li is often ignored in high-resolution spectroscopy. The hfs splitting of both the ground and the excited state are smaller than the Doppler width and thus are not resolved. In the spectroscopic investigation of argon lines parametric studies of the tuning behaviour of laser diodes have been performed. In addition to the well known mode hops during temperature tuning also relaxation oscillation side-bands to individual modes have been detected. In absorption spectroscopy of the three elements the spectra not only reveal the spectroscopic structure, but information on transition probabilities and particle number densities can be deduced as well.
12
Williams, R. L. „High resolution dynamic mechanical spectroscopy for dispersions“. Thesis, Swansea University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636626.
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Details of the design and development of an improved high frequency virtual gap rheometer, VGR, are presented. This rheometer utilises multiple path shear wave interferometry to determine the shear wave propagation characteristics (shear phase velocity (v) and damping length (xo) of colloidal dispersions from which viscoelastic parameters are derived. This VGR incorporates a data acquisition system (1MHz sampling rate; ≃ 8x106 samples) which allows measurement at frequencies (f) 200 ≤ f ≤ 2000Hz. The effect of digital quantisation, its relation to the operation of an electrostrictive actuator (source of shear waves), and to the design of test waveforms is considered. Protocols for the correct generation of waveforms are established. Measurements on a 'Newtonian' fluid (silicone oil) show that the VGR is able to determine the frequency dependent viscoelastic characteristics of dispersive systems. Test signals are analysed with high precision digital Fourier transform methods. This forms the basis for Fourier Transform Mechanical Spectroscopy (FTMS) which is developed for the VGR herein, allowing the use of up to eleven different frequency components simultaneously. A novel method for establishing linearity of the viscoelastic response is also reported. A low frequency (10-3→10Hz) rheological characterisation (conducted with a controlled stress rheometer) of aqueous, electrostatically stabilised dispersions of a clay colloid (Laponite XLG) is reported and establishes the suitability of these dispersions as a test material for the VGR. Measurements of v and δ(→ xo) with the VGR using sequential single frequencies and those conducted with simultaneous multiple frequencies (VGR FTMS), on equilibrium laponite dispersions, are in good agreement. The evolution of viscoelastic parameters with time, determined by VGR FTMS for equilibrating dispersions at various weight fractions, is reported. These results show that these dispersions exhibit marked viscoelastic wave dispersion over the frequency range of the VGR. Possible origins of wave dispersion are identified.
13
Dennis, Christopher Roger. „High resolution spectroscopy of open shell clusters“. Thesis, University of Oxford, 1997. http://ora.ox.ac.uk/objects/uuid:43ac8ad5-724a-4a23-a03f-3eb78e6f4e72.
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The microwave spectrum of the open-shell van der Waals complex NO-HF has been recorded in the region 6-20GHz using a pulsed nozzle Fourier transform microwave spectrometer. This is the first observation of the microwave spectrum of a open-shell van der Waals complex between two molecules. The spectrum exhibits a rich hyperfine structure with the observation of intermolecular hyperfine interactions in an isolated system providing a sensitive probe of electron transfer in the complex. The spectrum consists of four fine structure transitions 5/2(e)-3/2(e), 3/2(e)-1/2(e), 5/2(f)-3/2(f), 3/2(f)-1/2(f) which have been fitted to a semi-rigid Hamiltonian developed to include the effects of the orbital and spin angular momenta of the unpaired electron on NO. A new treatment to account for the intermolecular hyperfine interaction was developed. The structure of the complex has been determined and is significantly bent with an angle of between 37 degrees and 49 degrees between the NO internuclear axis and the a-axis of the complex. The Renner-Teller parameter, epsilon 2, is very large and negative having the value of -10 449.32(4)GHz indicating that configuration with the unpaired electron in the plane of the complex is more stable. The analysis of the hyperfine interactions of the hydrogen and fluorine nuclei uses two constants for each nucleus, one for the spatial relationship between the magnetic moments of the unpaired electron and the nuclear magnetic moment and a Fermi-contact term. The Fermi-contact term for hydrogen is the first strong evidence of intermolecular charge transfer in an isolated van der Waals molecule.
14
Bell, W. „High resolution spectroscopy of stratospheric trace species“. Thesis, University of Strathclyde, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325275.
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15
Elliott, Nicola Louise. „High resolution electronic spectroscopy of transient species“. Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443268.
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16
Elks, John Marcus Francis. „High resolution electronic spectroscopy of transient species“. Thesis, University of Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390790.
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17
Chandrakumar, Thambirajah. „The high resolution spectroscopy of manganese oxide“. Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/27405.
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This thesis reports studies of the electronic spectrum of gaseous MnO. The (0,0) band of the A⁶Σ +-X⁶ Σ+ electronic transition of MnO was recorded by intermodulated laser-induced fluorescence over the range 17770 - 17970 cm⁻¹. The hyperfine structure caused by the ⁵⁵Mn nucleus (I = 5/2) is almost completely resolved. Internal hyperfine perturbations between the F₃ and F₄electron spin components (where N = J - 1/2 and N = J + 1/2, respectively) occur in the ground state of MnO. These are caused by hyperfine matrix elements of the type ΔN = ΔF = 0.ΔJ = ± 1. Extra lines obeying the selection rules ΔJ = 0, ± 2 are also induced. Therefore, [sup P]Q₃₄, [sup R]Q₄₃, [sup P]Q₄₃ and [sup R]S₃₄ branches appear in the spectrum although they are not allowed in parallel transitions.
The reason for the great complexity of the spectra is the occurrence of a large avoided crossing near N = 26 in the A⁶Σ + v = 0 level by another electronic state, B⁶Σ +, with the same multiplicity and symmetry. The perturbation between the A⁶Σ + and B⁶Σ + states arises from electrostatic interaction. The selection rules for electrostatic perturbations are ΔJ = ΔS = Δ∧ = ΔΩ = 0. The perturbing state B⁶Σ + state has a considerably longer bond length so that it must come from a "charge transfer transition", possibly by electron transfer either from the 3π to the 4π orbital or from 8σ to 10σ. However, the A⁶Σ + state has only a small bond length change compared to the ground state so that it comes from a "Valence state transition". The Fermi contact constant b was found to be negative for the A⁶Σ + state and this confirms the electronic configuration as being (8σ² 3 π⁴) 1δ² 4 π ² 10σ¹.
The ground state is free of perturbations, except for the internal hyperfine perturbations, and is in nearly pure case (b) coupling. Various satellite branches which were observed in the B-X transition confirm the case (a) nature of the B⁶Σ + state at low N. The spacing between the main branches and the satellite branches gives values for the spin-spin parameter λ and the spin-rotation parameter γ of the ground state.Science, Faculty of
Chemistry, Department of
Graduate
18
Vander, Auwera Jean. „Quantitative high resolution Fourier transform infrared spectroscopy“. Doctoral thesis, Universite Libre de Bruxelles, 2004. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211133.
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Our work falls within the field of high resolution spectroscopy of gas phase molecules in the far-, mid- and near-infrared ranges. Its guiding line are absorption spectral intensities, dealt with experimentally and theoretically. In particular, we developed in our laboratory the field of intensities measurements of vibration-rotation lines using Fourier transform spectrometers, with a precision of about 0.5 % and an accuracy of 2-4 % for chemically stable species. We study chemically stable (CO2, N2O, C2H6, OCS, C2H2) and unstable (HOCl, HCOOH et HNO3) compounds. We also measure infrared absorption cross section spectra for CFC replacements. Some of our measured intensities, of direct interest for the study of planetary atmospheres, are now incorporated in international spectroscopic databases. Others are used to develop global theoretical models of molecules, in relationship with intra-molecular dynamics./Nos travaux de recherches relèvent de la spectroscopie à haute résolution de molécules en phase gazeuse dans les domaines de l’infrarouge lointain, moyen et proche. Ils ont pour ligne directrice les intensités spectrales d’absorption, abordées expérimentalement et théoriquement. Nous avons en particulier développé dans notre laboratoire le domaine de la mesure d’intensités d’absorption de raies de vibration-rotation à l’aide de spectromètres à transformée de Fourier. Nous réalisons ces mesures avec une précision d’environ 0.5 % et une exactitude d'environ 2-4 % pour les espèces chimiquement stables. Nous étudions des composés chimiquement stables (CO2, N2O, C2H6, OCS, C2H2) et instables (HOCl, HCOOH et HNO3). Nous mesurons également des spectres de sections efficaces d’absorption infrarouge pour des substituts des chlorofluorocarbures (CFC). Certaines de nos mesures d’intensité, d’intérêt direct pour l’étude d’atmosphères planétaires, sont aujourd’hui incorporées dans les bases de données spectroscopiques internationales. D’autres sont utilisées pour développer des modèles théoriques globaux de molécules, en liaison avec la dynamique intramoléculaire.Agrégation de l'enseignement supérieur, Orientation sciences
info:eu-repo/semantics/nonPublished
19
Goode, Jon G. „High resolution photoelectron spectroscopy of small molecules“. Thesis, University of Edinburgh, 1995. http://hdl.handle.net/1842/13932.
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The gerade Rydberg states of jet-cooled iodine have been thoroughly investigated in the region between 53000 and 70000 cm-1 using mass resolved (2+1) resonantly enhanced multiphoton ionisation (REMPI) spectroscopy. All the nd Rydberg states were found to be heavily perturbed through vibronic coupling with ion-pair states in contrast to most of the ns Rydberg states which were found to be unperturbed. The characterisation of these Rydberg states provided the basis for a comprehensive study of the two spin-orbit components of the ground state of the cation using two colour (2+1') ZEKE-PFI photoelectron spectroscopy. The ZEKE-PFI spectrum recorded for the lower spin-orbit state exhibits non Franck-Condon behaviour in contrast to that recorded for the upper spin-orbit state. This was interpreted in terms of an autoionisation mechanism involving Rydberg states converging on the upper spin-orbit component. Several new Rydberg states of the iodine-argon van der Waals complex have been investigated using mass resolved (2+1) REMPI spectroscopy in the region between 53000 and 69000 cm-1. The complex spectra exhibit anharmonic vibrational progressions in the I2 Ar van der Waals stretching mode in combination with the I2 stretching progression. The I2 Ar stretching frequencies and binding energies were found to increase with the principal quantum number of the Rydberg state which is consistent with a progressive strengthening of the van der Waals bond. This agrees with the expected reduction in effective shielding of the ion core by the Rydberg electron as it is excited into higher principal quantum number orbits. A (2+1') ZEKE-PFI investigation of the van der Waals complex cation revealed a very small binding energy increase in the ion compared to that determined for the n=8 Rydberg state. This small increase indicates that for Rydberg orbitals with n≥8 the effective shielding of the ionic core by the Rydberg electron is minimal.
20
Low, Russell John. „High resolution spectroscopy of weakly bound molecular complexes“. Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296861.
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21
Lawrence, Stuart John. „High-resolution spectroscopy of van der Waals molecules“. Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318824.
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22
Ruck, Martin. „High-resolution spectroscopy of G and K stars“. Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386575.
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23
Ashworth, Stephen Hugh. „The high resolution electronic spectroscopy of nickel dichloride“. Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302831.
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24
Dunn, James. „High resolution X-ray spectroscopy of laboratory sources“. Thesis, University of Leicester, 1990. http://hdl.handle.net/2381/35870.
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A detailed programme of research is presented to design, build and operate a high resolution h?hz5000 curved crystal Johann-type x-ray spectrometer for the waveband below 13A. The spectrometer is used to observe line emission features from different laboratory x-ray sources. Characteristics of the Johann geometry are described with emphasis given to the properties of sensitivity, dispersion, resolving power and waveband. The tolerance of the instrumental parameters is defined for successful high spectral resolution operation. The key feature of the spectrometer is the unique crystal bending device which can generate a high quality cylindrical curvature of radius R=150?5000mm. The crystal focusing alignment and testing procedures are evaluated. Choice of crystals suitable for the observation programme is discussed together with analysis techniques for interpretation of the x-ray spectral line profiles. The instrument is optimised for time-integrated and time-resolved ion temperature measurements of UKAELA DITE Tokamak at the Culham Fusion Laboratory. X-ray line emission results from medium Z He-like and H-like impurity ions are presented for different plasma conditions. Density sensitive He-like and Li-like Aluminium ion satellite emission features are studied for intense transient laser produced plasmas at the Central Laser Facility, SERC Rutherford Appleton Laboratory. The peak plasma electron density of 0.1 time solid density is estimated from these line intensity ratios and is in good agreement with Stark line width measurements. X-ray emission from beam-foil interactions is observed on the Folded Tandem accelerator of the Nuclear Physics Department, Oxford University. The proposed improvement in the intrinsic spectral line broadening due to the accelerator is investigated by high resolution axial beam measurements of the He-like Silicon and H-like Neon n=2 transitions. The Lyman-a intensity ?-ratio and wavelength separation ?hFS is studied for the fine-structure of Hydrogenic Neon, Magnesium, Aluminium and Silicon. The fine-structure separation is compared with the Dirac theory and other experimental data, while the possible mechanisms giving rise to the non-statistical value of the ?-ratio are analysed.
25
Brookes, Matthew Daniel. „High resolution infrared spectroscopy of jet-cooled molecules“. Thesis, University of Oxford, 1995. http://ora.ox.ac.uk/objects/uuid:81958380-6230-454d-bb44-bfb57d887749.
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The development and implementation of a high resolution, direct absorption, rapidscanning infrared diode laser spectrometer incorporating a supersonic jet expansion source is described. High sensitivity is achieved by directly modulating absorption signals at frequencies in excess of 50 kHz, enabling their separation from lower frequency mechanical and diode 1/f noise. This is accomplished by rapidly scanning the diode laser across a small frequency window (~0.5-1.5cm-1) synchronously with a pulsed supersonic expansion in a time period of 1 or 2 ms. Absorptions appear as small attenuations in the overall variation of the laser mode power across the scan window. This background profile is removed by recording the laser power without gas pulsing and subtracting. Relative frequency calibration is effected by simultaneously recording the spectrum of a reference gas and the interference fringes of an etalon. Absorption signals are recorded by means of a fast 12-bit analog-to-digital converter operating at 1 MHz. This is housed within a dedicated PC microprocessor which performs spectrometer control, data coaddition, signal processing and spectrum calibration functions. The spectrometer has been used to measure the infrared spectra of two weakly bound complexes, CO-OCS and Ne-SiH4. The infrared absorption spectrum of CO-OCS was measured in the 5μm region of the OCS ν3 asymmetric stretch. In addition microwave spectra of CO-OCS and two isotopomers 13CO-OCS and CO-OC34S have been recorded using a pulsed nozzle microwave Fourier transform spectrometer. The lines have been fitted to a Watson S reduction Hamiltonian yielding rotational, quartic and (for the ground states) sextic centrifugal distortion constants. A T-shaped structure is determined and this is rationalised by a simple potential model incorporating a distributed multipole analysis of the electrostatic charge distribution, distributed dispersion contribution and a cylindrical hard-core repulsion. The infrared spectrum of Ne-SiH4 was recorded in the vicinity of the SiH4 ν3 triply degenerate stretching vibration centred at 2189.19 cm-1. Ne-SiH4 is only the second atomspherical top complex to be successfully recorded and analysed. The complex exhibits an intermolecular potential with considerably smaller anisotropy than its argon analogue Ar-SiH4. Consequently the SiH4 unit is almost free to rotate within the complex, resulting in novel Coriolis interaction between the angular momentum of the SiH4 unit and that of the overall complex. Individual bands are fitted to Coriolis interaction Hamiltonians, and the band centres for all the transitions of the complex are fitted to an anisotropic intermolecular potential. Finally, applications of the spectrometer to the study of air sensitive compounds and species generated by electric discharge sources are considered.
26
Dowell, Nicholas G. „Further developments in high-resolution quadrupolar NMR spectroscopy“. Thesis, University of Exeter, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407274.
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27
Schubert, J. E. „High-resolution spectroscopy of small gas-phase radicals“. Thesis, University of Southampton, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354301.
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28
Cunningham, Mark Forrest. „High-resolution gamma-ray detectors for nuclear spectroscopy /“. For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.
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Thesis (Ph. D.)--University of California, Davis, 2003.Degree granted in Engineering, Applied Science. Dissertation completed in 2002; degree granted in 2003. Also available via the World Wide Web. (Restricted to UC campuses).
29
Gardner, Amy A. S. „Experiments toward high resolution spectroscopy of N+2“. Thesis, University of Sussex, 2016. http://sro.sussex.ac.uk/id/eprint/61452/.
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30
Crow, Martin Brian. „High resolution diode laser spectroscopy of transient species“. Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:64bd9688-fdb3-4d05-ac2b-2a9bb621bb7c.
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This thesis presents applications of near infrared diode lasers to high resolution spectroscopy of transient radical species. Firstly, time resolved near infrared laser gain versus absorption is utilised in Chapter 2 to determine the I∗ quantum yield following ultraviolet photolysis of iodobenzene and its fluorinated analogues. The experimental method is first confirmed by comparison with literature values of the quantum yield for iodomethane photolysis, returning a quantum yield of Φ(I∗) = 0.71 ± 0.04 in good agreement with the literature, before being applied to determine the I∗ quantum yield following 248 nm and 266 nm photolysis of iodobenzene (Φ(I∗) = 0.28 ± 0.04) and pentafluoroiodobenzene (Φ(I∗) = 0.32 ± 0.05). The I∗ quantum yields for 4-fluoroiodobenzene, 2,4-difluoroiodobenzene and 3,5-difluoroiodobenzene are also reported in order to determine the effect of selective fluorination on the dynamics of the photodissociation process. This work complements velocity-map ion imaging studies and spin-orbit resolved ab initio calculations of the ultraviolet photolysis of these compounds. Chapter 3 details the development of a narrow-bandwidth tunable continuous wave ultraviolet radiation source, through sum frequency mixing of tunable near infrared diode lasers with a fixed frequency, high powered, solid state laser. The application of the UV radiation source to spectroscopy of the A 1A2 − X 1A1 electronic band of formaldehyde is explored, where absolute absorption cross sections are determined for rotational transitions within the 220410 and 220430 vibronic bands. The sub-Doppler resolution has allowed refinement of the rotational constants for the slowly predissociating excited state of the 220430 vibronic band. The lifetimes of several rotational levels is determined to be in the range 0.74 ns to 1.46 ns. In Chapter 4 the UV radiation source developed in Chapter 3 is applied to the A 2Σ+ − X 2Π electronic band of the OH radical. Firstly, this source is utilised to probe a continuous supply of hydroxyl radicals using cavity-enhanced absorption spectroscopy and wavelength modulation spectroscopy. Pressure induced broadening parameters for the Q1(2) rotational transition for He, Ne, Ar and N2 buffer gases are also measured. Following the successful application of this source to probe a continuous OH source at atmospheric pressure, the UV spectrometer is used to probe OH radicals from nitric acid photolysis at 193 nm, where the nascent speed distribution and Doppler lineshape is shown to be in excellent agreement with the literature. Time resolved absorption spectroscopy of the nascent OH fragment also returns a translational relaxation constant of ktrans = (3.85±1.06)×10−10cm3molecule−1s−1, which is in good agreement with literature values. These preliminary results indicate the potential of this narrow-bandwidth tunable UV source as an absorption-spectroscopy-based probe of nascent Doppler profiles. Chapter 5 presents the application of frequency-modulated radiation from a near infrared diode laser as a probe of the angular momentum polarisation of the nascent CN fragments, produced by 266 nm photolysis of ICN. These CN fragments are probed in the high rotational states of both the ground and first excited vibrational level on the A 2Π − X 2Σ+ electronic transition; in particular these constitute the first measurements of alignment and orientation in the first excited vibrational level at this photolysis wavelength. The alignment parameters reported for both vibrational levels are comparable, indicating that the incoherent dynamics contributing to their formation are the same. In contrast, the orientation of the v = 1 CN fragment is shown to be of opposite sign to that of v = 0 at this photolysis wavelength, although the absolute differences in their orientation parameters are similar to that observed for photolysis at 248 nm. This observation is consistent with coherent orientation arising from phase differences between wavepackets propagating on multiple excited potential energy surfaces.
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Nakajima, Kaoru. „MONOLAYER ANALYSIS USING HIGH-RESOLUTION RUTHERFORD BACKSCATTERING SPECTROSCOPY“. 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/85403.
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Kyoto University (京都大学)0048
新制・論文博士
博士(工学)
乙第12399号
論工博第4030号
新制||工||1477(附属図書館)
27429
UT51-2009-M905
京都大学大学院工学研究科機械物理工学専攻
(主査)教授 木村 健二, 教授 井手 亜里, 教授 河合 潤
学位規則第4条第2項該当
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Lyne, Michael Peter. „High resolution spectroscopy of aminoborane and niobium nitride“. Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26442.
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The infrared spectrum of aminoborane (NH₂BH₂) was recorded by a Fourier transform interferometer and the 1550-1750 cm⁻¹ region of the spectrum was rotationally analyzed by a new search/match algorithm based on ground state combination differences. Sub-bands from four separate vibrational bands were discovered in this region. The interaction scheme was deduced to be a three-way anharmonic resonance between the V₃, V₇ + VB, and 2v₆ levels with the fourth level, V₆ + V₁₂ induced by a Coriolis mechanism with the members of the triad. The first order anharmonic constants were approximated by a least squares fit of the triad intensities: W₃₇₈ = 8.4±0.1 cm⁻¹, W₃₆₆ = 15.8±0.4 cm⁻¹ with W₇₈₆₆ held fixed at zero. Perturbations from unseen interloper levels plus the fully correlated nature of the pure vibrational anharmonic interaction prevented a successful fit of the rotational structure of this system. Both the search/match and the intensity least squares algorithms were developed for this work.
Four sub-bands in the red-orange region of the laser induced fluorescence spectrum of niobium nitride (NbN) were rotationally analyzed. Analysis of three sub-bands of the ³ϕ₂ - ³Δ₁ system allowed the vibrational spacings of each electronic state to be determined: ΔG½ = 986.351 cm⁻¹, ΔG1½ = 977.855 cm⁻¹ for the ³ϕ₂ state and ΔG1½, =. 1033.739cm⁻¹ for the ³Δ₁, state. The previously unassigned ³Π₁-³Δ₂ (0-0) sub-band was discovered 970 cm⁻¹ below its expected position of 18025 cm⁻¹. The electronic state assignment of this transition was confirmed by -wavelength resolved fluorescence measurements made with a diode array detector mounted on a spectrometer. A description of how the diode array detector was interfaced into the experiment is given.Science, Faculty of
Chemistry, Department of
Graduate
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Soman, Matthew. „High-resolution detectors for soft X-ray spectroscopy“. Thesis, Open University, 2014. http://oro.open.ac.uk/42020/.
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Resonant Inelastic X-ray Scattering (RIXS) is a modern soft X-ray spectroscopy technique used to investigate the structure of and excitations in materials. It requires high resolution spectrometers and a brilliant, tunable, X-ray source and therefore is carried out at spectrometers such as SAXES at the Swiss Light Source Light, a synchrotron at the Paul Scherrer Institut. SAXES uses a grating to disperse X-rays scattered from a sample across a position sensitive detector, a Charge-Coupled Device (CCD). It has been recognised that the spatial resolution of the CCD currently limits the spectrometer resolution and therefore the investigations described in this thesis focus on developing and testing methods of improving the detector resolution. Whilst this thesis addresses improving the resolution of the detector at SAXES specifically, the methods and results are applicable to other applications requiring high spatial resolution soft X-ray detection. After an introduction, Chapters 2 and 3 describe the importance of RIXS, operation of SAXES and background of soft X-ray detection in CCDs. A comparison of models that describe charge spreading in a CCD is in Chapter 4, and the best model is implemented in a simulation package that generates populations of soft X-ray events. Chapter 5 explores the resolution improvements possible through applying centroid algorithms to simulated X-ray events, and Chapter 6 begins by describing experimental work undertaken to verify simulation results. Due to the limitations of applying centroiding algorithms to the current SAXES camera, a small-area Electron Multiplying CCD (EM-CCD) is experimentally tested (Chapter 7). Results with the EM-CCD proved positive, therefore in Chapter 8 the spatial resolution achievable with a large area EM-CCD is verified for a future SAXES camera upgrade. Due to the successful results presented in this thesis, negotiations to develop a new camera system for SAXES are underway, and interest from other RIXS beamlines in the community may lead to the work also being applied elsewhere. The detection of soft X-rays with high spatial resolution is applicable to other future CCD and EM-CCD instruments, such as astronomical X-ray observatories.
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Abbouti, Temsamani Mohammed. „Acetylène, from high resolution spectroscopy to intramolecular dynamics“. Doctoral thesis, Universite Libre de Bruxelles, 1996. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212376.
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Odedra, Smita. „Some novel developments in high-resolution NMR spectroscopy“. Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/5772/.
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The radiofrequency (rf) pulses used in NMR are subject to a number of imperfections, such as those resulting from the inhomogeneity of the rf field or an offset of the transmitter frequency from exact resonance. In spin-echo experiments, these imperfections yield spectra with reduced signal intensity and distorted phase. Composite pulses, which have tailored bandwidth properties with respect to experimental frequency parameters such as the rf field strength or resonance offset, offer a route to improving the amplitude of the spin-echo signal. However, the symmetry of the pulse sequence must be carefully considered to prevent the introduction of phase errors into the spin-echo signal. Here, composite pulses will be studied as a means to improving one of the most common techniques for 1H background suppression in MAS NMR, the ”Depth” sequence. Novel composite 180° pulses will be presented for this application and verified experimentally. The composite pulse Depth experiment yields spectra with improved amplitude of the 1H signals of interest, while successfully maintaining good suppression of background signals. Novel families of dual-compensated 180° composite pulses for I = 1/2 will also be designed for use in NMR spin-echo experiments. These pulses are capable of simultaneously compensating for resonance offset and rf inhomogeneity problems. Crucially, unlike many composite pulses that have been presented before, these new pulses have the correct symmetry properties to form a spin echo without phase distortion. Composite pulses have found wide usage in solution-state NMR, and although in principle the same pulses can be applied in solid-state NMR experiments, complications can arise under magic angle spinning (MAS). The effects of MAS on composite pulse performance will be explored both through computer simulations and 31P experiments. Finally, on a different theme, we will investigate spin-locking of half-integer quadrupolar nuclei in solids. Spin-locking is an important feature of many NMR experiments, yet the complex behaviour observed for quadrupolar nuclei is not fully understood. Using the theoretical model introduced by Ashbrook and Wimperis, we will investigate the far off-resonance case of spinlocking for I = 3/2 and I = 5/2 nuclei.
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Vatter, Ian A. „High resolution microanalysis of alloy steel“. Thesis, University of Bath, 1993. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359723.
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Diaz, de la Rosa Mario Alfonso. „High-frequency ultrasound drug delivery and cavitation /“. Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1679.pdf.
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Pauley, Deanne Josephine. „High-resolution microwave spectroscopy of several weakly bound complexes“. Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185187.
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High resolution rotational spectra were obtained for a several weakly-bound complexes (WBC) and one transition metal organometallic molecule, cyclopentadienylnickel nitrosyl (CpNiNO), using pulsed-beam, Fourier transform microwave spectroscopy. The weakly-bound complexes included the two structural isomers of N₂O-HF, the planar bent asymmetric N₂O-HCN complex, the planar bent asymmetric N₂O-HCl complex, and the "stacked" H₂S-SO₂, and H₂S-CO₂ complexes. In all of the cases with the exclusion of the CpNiNO molecule, additional isotopic measurements were obtained to aid in the spectral and structural analyses of the weakly-bound complexes. Analysis of rotational spectra was used to determine several spectroscopic constants. For each WBC and CpNiNO rotational constants and some quartic distortion parameters were determined. In the experimental studies performed on N₂O-HCN and N₂O-HCl additional quadrupole coupling components were determined from the data analysis. Structural analyses were performed on all of the WBC's. Isotopic Kraitchman analysis was used as a comparative guideline in helping to select the lowest energy vibrationally-averaged structure. High resolution (0.005 cm⁻¹) infrared spectra for CpNiNO were obtained with the Fourier transform spectrometer in the Kitt Peak McMath Solar Telescope. Absorption spectra were measured in the 1750-1880 cm⁻¹ and 2500-3700⁻¹ regions. A program written by Dr. Clive Jarman, a postdoc in Dr. Peter Bernath's laboratory, was used to perform Loomis-Wood analysis of 2 significant patterns in the 2500-3700 cm⁻¹ range. The series determined from the Loomis-Wood analysis are given in the dissertation.
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Hodges, Philip J. „Transition metal halides, studied by high-resolution electronic spectroscopy“. Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433477.
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Jay, Victoria Louise. „Remote sounding of the atmosphere by high-resolution spectroscopy“. Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365439.
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梁詠霞 und Wing-har Joanne Leung. „High resolution laser spectroscopy of yttrium and nickel monohalides“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31243320.
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Walmsley, J. M. „High resolution laser photofragment spectroscopy of diatomic molecular ions“. Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384337.
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Price, Richard John. „Ultra-high-resolution spectroscopy of the ISM towards Orion“. Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252156.
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Leung, Wing-har Joanne. „High resolution laser spectroscopy of yttrium and nickel monohalides /“. Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?B25211742.
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Stowe, Matthew C. „Direct frequency comb spectroscopy and high-resolution coherent control“. Connect to online resource, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3315768.
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Keelan, Brian W. Zewail Ahmed H. „High resolution laser spectroscopy of supersonic jet-cooled molecules /“. Diss., Pasadena, Calif. : California Institute of Technology, 1986. http://resolver.caltech.edu/CaltechETD:etd-04032008-111202.
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Bannister, Nigel P. „The spectroscopy of DA white dwarfs at high resolution“. Thesis, University of Leicester, 2014. http://hdl.handle.net/2381/28720.
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This thesis is concerned with the spectroscopy of hot, hydrogen-rich white dwarfs, and the development of instrumentation with which to further their study. It begins with a review of white dwarf research, and a summary of results from some notable Extreme-Ultraviolet (EUV) missions. The absence of helium in hot hydrogen-rich white dwarfs is introduced, and the need to precisely determine their composition is explained. These issues provide motivation for the Joint Astrophysical Plasmadynamic Experiment (J-PEX). Using normal incidence, multilayer coated optics and a high resolution focal plane detector, this spectrometer offers a substantial improvement in effective area and spectral resolution over current instrumentation. The design and development of a microchannel plate (MCP) detector for J-PEX is discussed, and a study of MCP sensitivity enhancement processes presented. A CsI photocathode is found to offer superior performance in the 225 - 245 Å band covered by J-PEX. The low quantum efficiencies recently measured for MCPs are also discussed. A preliminary analysis of data from the first successful flight of J-PEX, on board a sounding rocket, is described. Techniques are devised to overcome uncertainties in wavelength calibration, leading to production of the highest resolution EUV spectrum currently available for an astronomical object. These data reveal the presence of helium along the line of sight to the white dwarf G191-B2B, and prove the value of the J-PEX design. Data from the Hubble Space Telescope and the International Ultraviolet Explorer are used to search for white dwarfs with highly ionised, non-photospheric absorption features. Three new identifications are made, in the white dwarfs REJ 1738+665, REJ 0558+165 and WD 2218+706. Possible explanations, including absorption by planetary nebulæ, are suggested. The spectra are of longer wavelength, but higher resolution than currently obtainable by J-PEX, and complement the latter instrument by resolving multiple velocity components along the line-of-sight. The importance of these measurements in the context of J-PEX results, is demonstrated.
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Pearson, Adrian. „High-resolution spectroscopy of rare-earth doped novel glasses“. Thesis, University of Southampton, 1994. https://eprints.soton.ac.uk/399137/.
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Spectroscopic investigations using high-resolution techniques of two novel rare-earth doped glasses are presented. By using high-resolution techniques, the effect of inhomogeneous broadening due to the incorporation of the ion into the glass host is reduced. The aim of this thesis is two-fold. Firstly, to show how the increased resolution these techniques provide can be used to study the ion-host interaction. Secondly, to use this knowledge to explain and predict the performance of the systems under study as components for the optical communications industry. Optical devices have already been demonstrated in the thulium doped fluoride glass ZBLAN. We present site-selective studies that show that the rare-earth ion can occupy two different site subsets within the glass. These subsets are shown to have radiative lifetimes that differ by greater than 10% at 4.2K. This difference, combined with the observation at room temperature of pump wavelength dependent fluorescence, is suggested as an explanation for the disagreement of modelled optical amplifier performance with measured results. Time resolved site selective studies of a highly doped sample allow for the investigation of the thulium-thulium energy transfer process. This allows it to be shown that the transfer process in the absence of resonant energy diffusion is phonon-assisted dipole-dipole transfer. In the search for an optical amplifier to work at 1.3µm, the rare-earth ion praseodymium is a popular candidate. However, to reduce the problems associated with non-radiative decay, glass hosts with low maximum vibrational energies are required. Two such hosts are ZBLAN and the chalcogenide glass Gallium-Lanthanum-Sulphide (GLS). Site-selective studies show that both glasses have spectroscopic features that may affect devices. In ZBLAN, two ion site subsets are again observed. In GLS, there is seen to be a large degree of correlation between the inhomogeneous broadening mechanisms affecting different energy levels. Combined with the room temperature site-selection observed, this will lead to an inhomogeneous amplifier system. In both praseodymium systems, it was demonstrated that persistent spectral holes could be burnt, allowing the homogeneous linewidth of the observed transition to be measured. By monitoring the wavelength dependence of the burning efficiency, it is seen that the interaction of the rare-earth ion with the host in ZBLAN differs greatly in the two site subsets.
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Berezkin, Kirill. „High-resolution infrared spectroscopy of the CH2 = CD2 molecule“. Thesis, Bourgogne Franche-Comté, 2018. http://www.theses.fr/2018UBFCK044/document.
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Dans cette thèse, nous avons considéré les spectres de la molécule CH2=CD2. Dans la partie expérimentale, nous avons enregistré des spectres infrarouges à haute résolution (~ 0,0025 cm-1) et fait une attribution complète des transitions enregistrées. Nous avons pu assigner pour la première fois un grand nombre de transitions des combinaisons peu intenses υ4+υ10, υ4+υ7 et de l'harmonique 2υ10; de bandes interdites par symétrie υ4, υ7+υ10, υ8+υ10; et des bandes «chaudes» υ7+υ10–υ10 et υ8+υ10–υ10. Pour la première fois, plus de 7000 transitions inconnues des bandes fondamentales υ2, υ3, υ6, υ7, υ8, υ10, υ12 et de l'harmonique 2υ7 ont été assignées. Sur la base de la théorie des opérateurs de perturbation et des propriétés de symétrie de la molécule étudiée, nous avons construit un hamiltonien effectif puis ajusté les énergies vibrationnelles expérimentales de quatorze états vibrationnels. De cette étude, il a résulté un écart-type pour l'ajustement d'environ (1,7–2,5)×10−4 cm−1 pour diverses régions spectrales. Nous avons également mesuré les valeurs expérimentales des intensités et des demi-largeurs et avons calculé les paramètres du moment dipolaire effectif et des coefficients d'auto-élargissement de la molécule CH2=CD2In this thesis we have considered spectra of the CH2=CD2 molecule. In the experimental part we recorded high-resolution (~ 0.0025 cm-1) infrared spectra and made full assignment of the recorded transitions. We were able to assign for the first time a lot of transitions to the weak combinations υ4+υ10, υ4+υ7 and 2υ10 overtone; forbidden due to the symmetry υ4, υ7+υ10, υ8+υ10; «hot» υ7+υ10–υ10 and υ8+υ10–υ10 bands. More than 7000 previously unknown transitions were assigned to the fundamental bands υ2, υ3, υ6, υ7, υ8, υ10, υ12 and 2υ7 overtone. On the base of operator perturbation theory and the symmetry properties of the studied molecule, we constructed an effective Hamiltonian and then fitted experimental ro-vibrational energies of fourteen vibrational states. As a result, rms-deviation of the fit was about (1.7–2.5)×10−4 cm−1 for various spectral regions. We measured also experimental values of intensities and halfwidths and calculated parameters of effective dipole moment and self-broadening coefficients of the СH2=СD2 molecule
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Panov, Sergey I. „Moderate and high resolution spectroscopy of transient molecular ions /“. The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487945015618952.
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