Dissertations / Theses: 'Laser spectroscopy'

1

Reppel, Julie-Ann. "Planar laser polarisation spectroscopy imaging in combustion /." Title page, abstract and table of contents only, 2003. http://web4.library.adelaide.edu.au/theses/09PH/09phr4259.pdf.

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2

Rogers, Kevin Shaun. "Laser desorption/laser ionization mass spectroscopy." Thesis, University of Salford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357037.

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3

Ekvall, Karin. "Time resolved laser spectroscopy." Doctoral thesis, KTH, Physics, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3063.

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4

Deeny, J. A. "Tunable diode laser spectroscopy." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253325.

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5

Davis, Ian Howard. "Far-infrared laser spectroscopy." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306442.

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Skelton, Mark Andrew. "Laser spectroscopy in a gas cell and collinear laser spectroscopy of '1'2'7'mBa." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279684.

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Dunfield, Kari. "Laser spectroscopy of ytterbium monofluoride." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq23791.pdf.

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8

Plimmer, Mark David. "Laser spectroscopy of atomic systems." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329991.

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9

Pang, Hon-fung, and 彭漢鋒. "Laser spectroscopy of iridium compounds." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B41508683.

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10

Shand, Neil Charles. "Laser multiphoton spectroscopy of aldehydes." Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/657.

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11

Butcher, Louise Sara. "Laser spectroscopy of caesium dimers." Thesis, University of Oxford, 1997. http://ora.ox.ac.uk/objects/uuid:dfd00a20-7f46-4828-8123-4f720980fb07.

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We have obtained spectra of 10 vibrational bands of the Cs₂ (2)³∏_u ← ϰ³∑⁺₉ system. The molecules were formed in a supersonic free jet expansion, and were excited by light from a single mode CW dye laser. The total laser induced fluorescence was measured at 90° to the incident light and molecular beam, using a photomultiplier. Using a slit system to image a selected part of the interaction region, we have reduced the Doppler width to about 350MHz. We have been able to resolve the discrepancy between the different vibrational band positions given in two previous papers. Our vibrational bands show broad rotational contours, but we have not been able to resolve individual rotational lines. We have also obtained rotationally resolved spectra of the bandhead region of 22 vibrational bands of the Β¹∏₉ ← X¹∑⁺_u system. We found that the frequencies of the bandheads agreed with the bandhead positions deduced from the Dunham coefficients of a previous work. We have developed a theoretical model of the rotational structure and intensity distribution, taking into account optical pumping and the small solid angle subtended by the detector. By fitting this model to the experimental spectrum of the v' = 3,u∿ = 0 band using least squares optimization, we were able to extract rotational constants and line positions. We found that these line positions were in good agreement with those from the previous work. We have discussed how such spectroscopic data may be used in a determination of the s-wave scattering length of caesium, and we have reviewed the validity of the scattering length and other pararneterisations of low energy Cs-Cs interactions.

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12

Rodgers, David John. "Laser photofragment spectroscopy of OH'+." Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238198.

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13

Huang, Ping. "Diagnostics in VUV laser spectroscopy." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/2244.

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Thesis (MSc (Physics))--University of Stellenbosch, 2005.
A tunable vacuum ultra-violet (VUV) laser source was recently developed for VUV spectroscopy using state selective excitation and total fluorescence detection. The VUV laser source makes use of a four-wave mixing process to provide tunable VUV radiation for the electronic excitation of the molecules. The theory of four-wave mixing, with the emphasis on parameters that are important for our experimental setup to generate efficient tunable VUV radiation is discussed. The experimental setup, and in particular the metal vapor heat-pipe, which provides Mg vapor as the nonlinear medium, is described. New diagnostic equipment described in this work was added to the experimental setup. This equipment was characterized and utilized together with the existing setup. The additional diagnostic equipment introduced enabled us to measure the tunable VUV output of the source (using a VUV monochromator), making it possible to significantly improve the efficiency of the existing tunable VUV laser source.

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Pang, Hon-fung. "Laser spectroscopy of iridium compounds." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B41508683.

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Naiim, Habib Marie. "Caractérisation d'une source de particules de carbone créée par ablation laser pour calibrer les mesures d'érosion par spectrosamakcopie dans un tok." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX22122/document.

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Dans un tokamak, les interactions entre le plasma et la paroi conduisent à l'érosion des composants face au plasma. Celle-ci peut nuire au fonctionnement et à la sûreté du tokamak. Afin de respecter les limites imposées pour la sûreté du projet ITER, il est donc nécessaire de contrôler la quantité de matière érodée. La spectroscopie optique d’émission dans le domaine visible est traditionnellement utilisée pour mesurer des flux de particules de la paroi vers le plasma. Ces mesures sont permises grâce à un modèle collisionnel-radiatif s’appuyant sur des données de physique atomique. Cependant, ces données ne prennent pas en compte la géométrie d’observation du diagnostic de spectroscopie, et présentent des incertitudes relativement importantes. D'autre part, les phénomènes de transport, de déposition et de ré-érosion, ainsi que la modification de la transmission ou de la réflexion des optiques peuvent conduire à une mesure erronée de la quantité de matière effectivement érodée. Une méthode de calibration in situ, qui consiste à injecter par laser une source connue de particules de carbone dans la ligne de visée du diagnostic de spectroscopie pendant les décharges plasma, est proposée. L’étude expérimentale de l’ablation laser du carbone a permis de déterminer les conditions optimales à la constitution de cette source, et de caractériser les espèces ablatées. Ces expériences sont complétées par une modélisation du spectre d’émission du plasma induit par laser, afin d’obtenir des informations sur son degré d’ionisation. Enfin, les résultats des premières expériences de validation réalisées sur le tokamak allemand TEXTOR sont présentés et discutés
In a tokamak, plasma-wall interactions lead to the erosion of plasma facing components, which can be detrimental to plasma operation and to the safety of the tokamak. In order to fulfil the safety requirements imposed to the ITER project, it is necessary to monitor the amount of eroded material. Optical emission spectroscopy in the visible range is traditionally used to measure particle fluxes from the wall to the plasma. These measurements are done thanks to a collisionnal-radiative model based on atomic physics data. However, these data don’t take into account the observation geometry of the spectroscopic diagnostic, and suffer from relatively large uncertainties. Furthermore, transport, deposition and re-erosion phenomena, as well as the evolution of the transmission or the reflection of optical components can lead to an incorrect estimation of the amount of effectively eroded material. An in situ calibration technique, which consists in injecting by laser a known carbon particle source in the line of sight of the spectroscopic diagnostic during plasma operation, is proposed. The experimental study of laser ablation of carbon allowed to determine the optimal conditions for the constitution of this source, and to characterise the ablated species. These experiments are completed by a modelling of the emission spectrum of the laser induced plasma, in order to obtain information on its ionisation degree. Finally, results of the first validation experiments realised in the German TEXTOR tokamak are presented and discussed

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16

Tolchard, J. M. "Doppler free laser spectroscopy of atomic hydrogen using pulsed lasers." Thesis, University of Southampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383868.

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Billingham, Helen. "Quantum cascade laser spectroscopy : non-linear optics and population transfer." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:16e54542-c2f4-46ce-81a7-621619dd3b2e.

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This thesis is concerned with the non-linear effects observed in the absorption spectra obtained with swept continuous wave quantum cascade laser (cw-QCL) radiation. The slower chirp rate afforded by cw-QCLs, compared with pulsed systems, allows different aspects of the population transfer and polarisation induced in a molecular transition to be elucidated: namely, adiabatic rapid passage and coherent transient effects. The thesis commences with a brief outline of the architecture of QCLs, and an introduction to the non-linear processes inherent in their utilisation. In the following chapter, an outline of the methods required to characterise and drive a QCL chip are described along with the theory and characterisation of a Herriott cell, the latter allowing optically thick but minimally damped samples to be investigated. In chapter 3, a cw-QCL operating at ~10 μm is employed at chirp rates near to the adiabatic limit, in the range 0.1-1.1 MHz ns-1. A ro-vibrational overtone transition of OCS is studied at two path lengths within an astigmatic Herriott cell, 238 and 47 m. The population transfer and non-linear effects induced by the cw-QCL are described and modelled using the Maxwell-Bloch equations, which incorporate different experimental parameters. As such, the maximum population transfer found at a low pressure of 4 mTorr was determined to be 12 %. Additionally, the maximum amplitude of the coherent transient is forced to shift markedly to later times as the sample becomes increasingly optically thick, whilst remaining minimally damped. Intrapulse spectroscopy with a cw-QCL operating at 4.6 μm is investigated in chapter 4. The laser's response to short current pulses, in the range of 20-400 ns, applied in conjunction with a slow ramp, 2.75 kHz ns-1, is characterised. The initial chirp rate during the pulse is found to be ~6 MHz ns-1 by observation of the temporal width of transitions within the pulse. After the pulse a down chirp, at a rate of ~1 MHz ns-1, caused the laser frequency to relax back to the frequency position prior to the pulse. Subsequently, the effect of the pulse on a strongly absorbing N2O transition is monitored. In particular, the pulse position is altered with ii Quantum Cascade Laser Spectroscopy: Non-Linear Optics and Population Transfer respect to the transition line-centre and the coherent transient response of the molecular sample is probed. The free induction decay and RP effects noted are found to have a beat frequency which alters in line with the chirp rate of the laser, and the decay time of the transient signal was found to decrease as the range of velocity groups swept through is increased. The non-linear response of optically thick NH3 is investigated in chapter 5 with a 30 mW laser operating at ~10 μm. The effect of changing the gas pressure, laser intensity, and chirp rate on optically thick transitions is investigated for this molecule, which has a markedly larger dipole moment than OCS, and a comparison between the three molecular systems studied in this thesis is presented. Due to the importance of velocity dephasing in this work, the linewidth of the QCL was measured by Lamb-dip spectroscopy and found to be ~3 MHz. Two noise sources are then employed to alter the linewidth of the QCL: a single frequency modulation and a random white noise source. The noise, applied through the bias-T of the laser, leads to a change in the linewidth and lineshape, and as such, user-selectable linewidths in the range 3-20 MHz can be created. Increasing the laser linewidth has been found to increase the saturation of the sample, and therefore leads to an increase in the population transfer, which is determined to be ~10% at a chirp rate of ~0.1 MHz ns-1. The final chapter introduces the first use of a cw-QCL for population transfer within a molecular beam. The excited state is probed via resonantly enhanced multiphoton ionisation time of flight (REMPI-TOF) spectroscopy and a velocity selected population transfer of ~8 % is achieved. The effects of laser intensity, molecular beam carrier gas and laser linewidth on the population transfer are investigated. This thesis concludes with a discussion of some potential extensions to the work presented in this final chapter.

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18

Jacobs, Robert Michael James. "Laser studies of plasmas." Thesis, University of Oxford, 2000. http://ora.ox.ac.uk/objects/uuid:3de1c919-d7ce-485c-94c8-e5ab9e8e4a4b.

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Measurement of the intrinsic properties of processing plasmas is critically important in understanding discharges so that the optimum conditions can be achieved. Several different diagnostic methods have been developed and tested. A planar probe has been used to measure the ion flux and electron temperature in both inductively coupled and capacitively coupled plasma systems, at various pressures and applied powers, using the assumption that the electron energy distribution is a Maxwellian.

Frequency modulation spectroscopy (FMS) has been used to detect species in a plasma. It has been shown to be very effective, giving a significantly increased S/N ratio compared to both single pass absorption and low frequency mechanical modulation techniques. It has been used to measure excited argon atom concentrations, in both capacitively and inductively produced plasmas. The argon atom 4s[3/2]₁ level concentration was found to be between 2 x 10⁸ and 1 x 10¹¹ atom/cm³ and to generally increase with increasing applied power and to decrease with increasing total pressure. The temperature of the atoms was also measured and was found to be approximately 323 ± 17 K. A simple compact laser source at 308 nm has been produced from a frequency doubled cooled commercial diode laser. This has been used to detect the OH radical, by absorption, within the afterglow of a microwave discharge, produced either directly or chemically. Simple kinetic models have provided explanations of the variations in OH concentration with discharge conditions. A novel method, cavity laser induced fluorescence (CLIP), that combines the advantages of both laser induced fluorescence (LIF) and cavity ring down spectroscopy CRDS, has been shown to increase the sensitivity of a diagnostic system compared to absorption. This method could be used to follow concentration variations of a reaction in a single laser shot. Although such variation can be observed using LIF, it requires a calibration and a many laser shot experiment with a signal recorded at each time point. Whilst CRDS allows temporal information about the absolute concentrations of the species observed to be obtained, it is not as sensitive as LIF. By combining the two in CLIP, it may be possible to retain the sensitivity of LIF with the advantage of CRDS so that absolute and time varying concentrations can be obtained in a single pulsed laser shot. LIF and CRDS signals have been observed using the A ²?_u ? X ²S_g⁺ transition of the N₂⁺ ion. The lifetime of the A ²?_u state in the discharge was found to be sufficiently long for a time of flight experiment to be contemplated (an ion with a velocity of 10 kms^-1 on average would travel 5 mm before radiating). Although the preliminary tests for the time of flight experiment have shown that this method is not feasible with a pulsed laser, the basic cavity locking procedures required for an analogous continuous wave experiment have been successfully demonstrated. A frequency doubled diode laser source has been constructed and tested, with the eventual aim of detecting N₂⁺ via the B ²S_u ? X ²S_g⁺ electronic transition. This has been found to be insufficiently intense to be used for a proposed two dimensional velocity mapping experiment, but several strategies to improve its performance are suggested.

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19

Ho, Sut Kam. "Highly sensitive elemental analysis of ArF laser excited atomic fluorescence of laser plumes." HKBU Institutional Repository, 2007. http://repository.hkbu.edu.hk/etd_ra/765.

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20

Kiehn, G. P. "XUV laser amplication in recombining laser produced plasmas." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379973.

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Chan, Sui Yan. "Resonance-enhanced laser-induced plasma spectroscopy for elemental analysis." HKBU Institutional Repository, 1999. http://repository.hkbu.edu.hk/etd_ra/184.

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22

Lazzouni, M. "Laser spectroscopy of rare earth compounds." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235038.

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Woodman, George Henry. "Precise laser spectroscopy of atomic hydrogen." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316894.

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Plaut, Annette Sally. "Laser spectroscopy of semiconductor quantum wells." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.258014.

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Hansen, Peter C. "Laser spectroscopy of rare earth ions." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293472.

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Sanders, Scott Edward. "Laser spectroscopy of wire-like molecules." Thesis, Durham University, 2012. http://etheses.dur.ac.uk/3482/.

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Cavity-enhanced Laser-Induced Fluorescence With the incorporation of a new optic mount and focussing lens a cavity ring-down set-up was altered to collect fluorescence signal from molecules seeded in a molecular beam. Running both the CRDS and fluorescence measurements simultaneously produced a technique with significantly enhanced sensitivity compared to either of the two individual methods. Preliminary analysis with SO2 and a selection of polyaromatic molecules point to the method been best suited for measuring the fluorescence spectra of fast fluorescence lifetime (< 1 ns) molecules and in confined environments i.e. molecular beams. This has been characterised using a known sample and also compared to the CRDS and fluorescence measurements ran as individual techniques. The method was found to increase the sensitivity of the current experimental set-up by two orders of magnitude. This was then applied in the analysis of two new molecular samples to obtain spectra for use in analysing the torsional motions within the molecule. Torsional Motion Analysis of 2,5-bis(phenylethynyl)thiophene Torsional motions in polyphenyls, potential molecular wires, are important in the charge carriage capability of the species. Using a combination of UV-cavity ring-down and fluorescence detection the absorption and photoexcitation spectra of 2,5-bis(phenylethynyl)thiophene were successfully measured. Using a simple cosine potential and simulation program the spectra were reproduced and were found to be close to the values determined in previous research on the two ring system tolane and 1,4-bis(phenylethynyl)benzene.

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Lewis, W. P. "Spectroscopy of laser-produced plasma plumes." Thesis, Swansea University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637893.

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The primary objective of the work described in this thesis is to examine the plume of neutral and ionized vapour generated when an intense pulsed laser beam is incident on a target surface and to ascertain optimum conditions to ensure that the optical emission produced from the plume, which is in effect a high temperature plasma, could be used for spectroscopic analysis of the target material. This use of a focused laser beam to yield information concerning the elemental nature of the material is generally known as Laser-Induced Breakdown Spectroscopy (L.I.B.S.). In addition it was hoped that the constituents of the plume might be further analysed by inducing fluorescence from the atoms present. The present thesis describes the investigations which commenced in 1984 in an empty laboratory and with very little equipment. The initial phase was essentially the design, construction, assembly and characterization of apparatus and the design of relevant experiments. Details of the tunable dye laser, associated control electronics and vacuum and gas-handling equipment and target mounting and target chamber are described. Characteristics of the laser system were measured and are discussed. Observations of the emission spectra of various laser-produced plasmas from a number of targets are described and discussed. Although the preliminary work by the author ended in 1988 it laid the foundations for further L.I.B.S. work in the laboratory and which has led to the submission of theses, presentations and publication of papers (Goddard 1990, Allott 1992, Williams 1993, Davies 1994). The present work constitutes the essential precursor to the work of Goddard, Allott, Williams and Davies.

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江河 and He Jiang. "Laser spectroscopy of transition metal nitrides." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31240380.

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譚偉信 and Wai-shun Tam. "Laser spectroscopy of transition metal monosulfides." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31244816.

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Simpson, Alexander William. "Laser spectroscopy and photophysics of perhalonitrosomethanes." Thesis, Heriot-Watt University, 1993. http://hdl.handle.net/10399/1468.

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31

Batey, Andrew David. "Laser photofragment spectroscopy of molecular ions." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283638.

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Levick, Andrew Philip. "Laser photofragment spectroscopy of molecular ions." Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277619.

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England, J. G. "Laser resonance spectroscopy of samarium isotopes." Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374792.

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Demir, Arif. "Spectroscopy of X-ray laser media." Thesis, University of Essex, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361175.

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Al-Obaidi, Ala. "Synthesis and laser spectroscopy of porphyrins." Thesis, University of York, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.290870.

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Smith, David Murray. "Diode laser spectroscopy of silane plasmas." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259622.

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Macdonald, James William. "Laser photoionisation spectroscopy of silver dimer." Thesis, University of Edinburgh, 1993. http://hdl.handle.net/1842/11074.

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A number of experimental techniques have been brought together to create a powerful investigative tool. This laser vaporisation, supersonic expansion, laser ionisation mass spectrometry amalgam has allowed the study of two distinct types of molecular species. Many heteronuclear diatomic species have been prepared and investigated for the first time. These novel molecules are of interest due to their utility as bulk phase alloys. Mass spectra are presented for many such combinations. Homonuclear diatomic species have been analysed using these techniques for some time. In particular, this work has focused on transition metal species as this is one of the few methods which permits such study. Spectroscopic investigations of the A, B and C states of the silver dimer (Ag₂) molecule are presented here. The analysis of this work has provided the following rotational constants for these states; X state B_e = 0.04878 cm^-1 A state B_e = 0.04432 cm^-1 B state B_e = 0.04544 cm^-1 and C state B₀ = 0.04851 cm^-1. All values are for the ^107,109Ag₂ isotopomer. The first ionisation potential (I.P.) of any molecular system is an important parameter in the understanding of that species. The value of the I.P. has been evaluated for the silver dimer molecule under differing experimental conditions. It is reported here both under the influence of a potential field (I.P. = 61658.4 cm^-1) and under field free conditions (I.P. = 61740.0 cm^-1).

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Jiang, He. "Laser spectroscopy of transition metal nitrides /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21527076.

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Miller, Bradley E. "Vacuum ultraviolet laser spectroscopy of small molecules." Diss., Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/27891.

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Khalaf, Shhab Ahmed Abdolah. "Spectroscopy and dynamics of small molecules using laser and microwave spectroscopy." Thesis, University of Sussex, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296535.

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Ayyalasomayajula, Narasimha Rao. "Nd:YAG mini slab laser hybrid integration and Raman sensor application /." Morgantown, W. Va. : [West Virginia University Libraries], 2009. http://hdl.handle.net/10450/10437.

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Thesis (Ph. D.)--West Virginia University, 2009.
Title from document title page. Document formatted into pages; contains xiv, 170 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 159-164).

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Bopegedera, A. M. Ranjika Priyadarshi. "Dye laser and diode laser spectroscopy of gas phase free radicals." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184695.

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The gaseous free radicals, alkaline-earth metal monoalkylamides, monoacetylides, monoformamidates and monopyrrolidates, consisting of a metal atom (Ca or Sr) bonded to a single ligand, were synthesized in a Broida oven. The electronic and vibrational structures of these molecules were studied by low-resolution laser spectroscopy techniques. These inorganic molecules are ionic, well represented by the structure M⁺L⁻ (M = Ca, Sr: L = ligand). Three electronic transitions were identified for the metal monoalkylamides and the metal monoformamidates. The formamidate anion bonds to the metal in a bidentate fashion through the oxygen and nitrogen atoms. Two electronic transitions were observed for the metal monopyrrolidates. The pyrrolide anion ring bonds to the metal to provide these "open-faced sandwich" type molecules with pseudo-C₅ᵥ symmetry. For the metal monoacetylide molecules, only one electronic transition (Ā²Π-Ẋ²Σ⁺) was observed. Several vibrational frequencies were determined for these inorganic molecules from the low-resolution spectra. The Ā²Π-Ẋ²Σ⁺ transition of the calcium monoacetylide molecule was rotationally analyzed at high-resolution using the filtered laser excitation spectoscopy technique. The rotational line positions were fitted to a ²Π-²Σ⁺ Hamiltonian to obtain several rotational constants. The calcium-carbon bond length in CaCCH was calculated for the ground (2.248 Å) and excited (2.200 Å) electronic states. The vibration-rotation spectra of the gaseous bismuth hydride and bismuth deuteride molecules were recorded, using a diode laser system. The 1-0 fundamental band and several hot bands with Δv-1 were rotationally analyzed. The rotational line positions were fitted first, to a Dunham energy expression and then to a ³Σ⁻ Hamiltonian, to obtain ground state rotational constants. The bismuth-hydrogen (deuterium) bond distance was calculated to be 1.809 Å (1.807 Å).

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Cousin, Agnès. "LIBS (Laser-induced breakdown spectroscopy) pour l'exploration martienne." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1655/.

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ChemCam est à bord de la mission Mars Science Laboratory (MSL) qui a décollé pour Mars le 26 novembre 2011. Cet instrument est très innovant car c'est la première fois que la technique du LIBS ("Laser-Induced Breakdown Spectroscopy") est utilisée pour l'exploration planétaire, afin d'étudier la géochimie des sols et roches à la surface de la planète rouge. Cette technique permet de déterminer la composition chimique de la cible analysée, en focalisant un laser à sa surface. Un plasma se créé alors par échauffement de la matière. L'analyse spectrale de la lumière émise du plasma permet d'identifier les éléments présents dans la roche, ainsi que leur concentration. Ce travail de thèse contribue à la préparation du retour scientifique de la mission MSL et de l'instrument ChemCam autour de quatre axes principaux : (i) identification et caractérisation des raies spectrales pertinentes, (ii) test des méthodes de classification des roches avec ces mesures, (iii) étude de la sensibilité aux vernis d'altération des roches ou à la couche de poussière, (iv) analyse des données pour extraire des informations sur la structure et la composition des roches. Une station sol a été développée afin de reproduire les conditions atmosphériques à la surface de Mars. Une bibliothèque de raies élémentaires a été réalisée. Cette dernière est spécifique à ChemCam et à la géochimie de Mars, et contient plus de 1300 raies. Les outils de classification des roches avec les données de ChemCam se sont montrés efficaces. ChemCam permet de réaliser des analyses quantitatives, que ce soit par des méthodes statistiques ou plus conventionnelles. Nous avons montré que cet instrument est capable d'analyser aussi-bien la couche d'altération d'un basalte que la roche saine au dessous. Il permet également d'effectuer des analyses très fines, comme la comparaison de différentes matrices de roches volcaniques, ou encore de la structure interne des argiles. Pour finir, ces études expérimentales réalisées durant la thèse ont démontré que ChemCam répondait à toutes les spécifications imposées au début de sa conception
ChemCham is onboard the Mars Science Laboratory (MSL) mission, which was launched the 26th November 2011. This instrument uses the LIBS (Laser-Induced Breakdown Spectroscopy) technique to study the geochemistry of the Martian surface. This technique is used for the first time for the Space and Planetary exploration. In LIBS technique a pulsed laser beam is focused on a target, creating a plasma. The spectral analysis of the plasma light is collected to observe the characteristic emission lines of the elements present in the sample. This work contributes to the preparation of the scientific returns of the MSL mission but also of ChemCam, with four principal axes: - identification and characterization of the significant elemental lines, - test of the method used to distinguish rocks with these measurements, study of the capacity to analyze the alteration coating on rocks, - data analysis to extract informations about the structure and/or composition of rocks A ground station was developed in order to be representative of the Martian surface conditions. An elemental lines database specific of ChemCam and Mars is performed, with up to 1300 lines. Several experimental studies let us to characterize some of the ChemCam capabilities. First, rocks classification is successful whatever the kind of the sample. Some parameters were studied to understand their influence on the classifications. Then, quantitative analysis with ChemCam are feasible, not only using statistical methods. We show that ChemCam is able to analyze the composition of the alteration coating before the one from the unaltered rock, deeper. It is also able to make some differences between several kinds of basalts with their texture and matrix, and between several kinds of clays, looking at their internal structure

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44

Rauschenberger, Jens. "Phase-stabilized Ultrashort Laser Systems for Spectroscopy." Diss., lmu, 2007. http://nbn-resolving.de/urn:nbn:de:bvb:19-71104.

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45

Bauer, Michael. "Raman spectroscopy of laser induced material alterations." Diss., lmu, 2010. http://nbn-resolving.de/urn:nbn:de:bvb:19-117196.

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46

Corlett, Gary Keith. "Laser spectroscopy of metal-containing free radicals." Thesis, University of Leicester, 1997. http://hdl.handle.net/2381/30046.

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Laser-induced fluorescence (LIF) spectroscopy has been used to probe the properties of several metal-containing free radicals, prepared in a supersonic jet expansion by either an electrical discharge or by laser ablation/photolysis. The first spectroscopic observation of the zinc monoethyl radical was carried out following an electrical discharge through a mixture of zinc diethyl and helium. The laser excitation spectra recorded contained extensive vibrational structure, and a partial assignment is presented with the aid of ab initio SCF calculations. This was the first time an electrical discharge had been used to prepare a binary organometallic intermediate in a supersonic jet. LIF excitation and dispersed fluorescence spectra of the MgCCH free radical were obtained following laser ablation of magnesium metal in the presence of methane. This was the first observation of the electronic spectrum of MgCCH, and vibrational progressions in the metal-carbon stretching mode were assigned for both the XËœ2sum+ and A 2pi electronic states. Other weak vibrational structure attributable to metal-carbon bending and carbon-carbon stretching modes is also tentatively assigned. In addition, the rotational constant was found for the A 2pi state following a simulation of the observed rotational structure. Laser ablation of calcium and strontium in the presence of benzene gave intense LIF spectra of several well-known and one unknown species. Subsequent analysis of the observed vibrational structure led to the conclusion that the CaCCCH3 and SrCCCH3 free radicals were the spectral carriers, respectively. This task was aided by a series of density-functional theory calculations. This is the first spectral observation of both species. Initial attempts at characterising the alkali metal monoxides by LIF spectroscopy are also presented. These intermediates were to be prepared by laser ablation of the corresponding metal in the presence of N2O. Early experiments focused on the monoxides of Li and Na, and currently only Li + N2O has produced an LIF spectrum. The observed structure, which is quite complex and not amenable to any simple assignment, has been tentatively assigned to the C2pi -- X2pi and C2pi -- A2sum+ systems of LiO. These preliminary findings bode well for future studies of the heavier alkali monoxides.

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47

Lithgow, Gregg Arthur. "Aerosol measurements with laser-induced breakdown spectroscopy." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3257394.

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Thesis (Ph. D.)--University of California, San Diego, 2007.
Title from first page of PDF file (viewed May 17, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.

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48

Cocolios, Thomas Elias. "Collinear fast-beam laser spectroscopy at ISAC." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97933.

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Collinear fast-beam laser spectroscopy is a method of studying atomic and ionic hyperfine structure where a particle beam and a laser beam are superposed along the same line. Such a facility exists at ISAC, TRIUMF, Vancouver, BC, and was designed especially for polarising radioactive beams of alkali metals.
In order to produce polarised fluorine for the use in NMR, the hyperfine structure of the 3s 4P 5/2 and 3p 4D 7/2 states has to be known. The hyperfine coefficients for those two levels are measured for the first time to be A = 2645.6(6) MHz and A = 1565.6(4)MHz respectively. The 3p 4D5/2 state is also studied to measure the metastable atom fraction and its hyperfine constant is measured to be A = 1148(5)MHz.
A study of lanthanum ions is also carried out. Spectra for the 6 s2 1S0 to 5 d6p Do13 transition are measured with stable 139La to evaluate the sensitivity of the equipment and with radioactive 139La for preliminary commissioning of the isotope shift study.

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Hutt, K. W. "Far-infrared laser spectroscopy of disordered solids." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373250.

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Gray, Andrew James. "Higher resolution laser-radiofrequency double resonance spectroscopy." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259598.

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Dissertations / Theses on the topic 'Laser spectroscopy'

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