Dissertations / Theses on the topic 'Terahertz gas phase spectroscopy'
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Zhang, Yaqing Ph D. Massachusetts Institute of Technology. "Two-dimensional terahertz rotational spectroscopy in the gas phase." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122715.
Cataloged from PDF version of thesis.
Includes bibliographical references.
Two-dimensional (2D) coherent spectroscopy has been developed to study molecular dynamics and structures for decades, but its extension into the terahertz (THz) regime remains rare. In this thesis, I describe several experiments using two-dimensional terahertz rotational spectroscopy. Employing intense THz electromagnetic fields and the differential chopping technique, we have extended multi-dimensional coherent spectroscopy into the THz regime. We have observed rotational dynamics of linear, symmetric-top, and asymmetric-top molecular species, indicating that 2D THz spectroscopy is an incisive tool for investigating collective quantum effects of the rotational degree of freedom. Based on the quantum mechanical rigid rotor model, we have developed simulation and calculation approaches to disentangling spectroscopic signals from molecular rotations.
We have shown ultrafast 2D THz photon echo spectroscopy of gaseous acetonitrile samples, revealing J-state-resolved rotational dynamics in symmetric-top molecular rotors. We have revealed nonlinear rotational couplings and many-body interactions in water vapor, uncovering the strongly correlated nature of rotational quantum states in water molecules. Additionally, experimental evidence of linear and nonlinear THz spectroscopy of stable water dimers in the vicinity of atmospheric conditions has been observed. We have reported dual-type rotational couplings and a propensity for the K-state-dependent cross-peaks in sulfur dioxide, highlighting distinct rotational properties in slightly asymmetric-top molecules. We have measured the quartic THz effect using two-dimensional THz-Raman hybrid spectroscopy, opening the way for understanding and applications of higher-even-order THz-matter coherences beyond the linear and quadratic THz field effects.
Utilizing the density matrix and time propagation approaches, we have developed a set of simulation and calculation methodologies to characterize rotational dynamics in the gas phase based on the quantum mechanical rigid-rotor model. Our work shows the remarkable capability of 2D THz spectroscopy to interrogate rotational dynamics in the gas phase, laying a foundation for understanding and manipulation of nonlinear light-molecule interactions via multi-dimensional coherent THz spectroscopy.
by Yaqing Zhang.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Chemistry
Mahé, Jérôme. "Far infrared/Tera-Hertz spectroscopy in the gas phase : experiments and theory." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLE043/document.
Infrared spectroscopy allows the assignment of three dimensional structures of molecular systems, by comparing experimental and theoretical spectra. Our investigations take place in the gas phase, where molecules and clusters are free of intermolecular interactions.Our work combines experimental IR-UV ion dip spectroscopy and theoretical DFT-MD anharmonic spectroscopy. The infrared spectrum is calculated for low energy 3Dstructures and the best match between theory and experiment provides the information about the structure present in the experimental conditions.We demonstrate for several systems that far infrared/THz spectroscopy (<800 cm-1, <24THz) allows conformational assignment without ambiguities, contrary to the more traditional 1000-4000 cm-1 range. Systems investigated here are dipeptides, a β-sheet model, phenol derivatives (also complexe dwith water molecules), DNA base pairs, all these structures being built on intra-/intermolecular hydrogen bonds
Elmaleh, Coralie. "Développement d’un prototype ultrasensible d’analyse de gaz dans le domaine submillimétrique." Electronic Thesis or Diss., Littoral, 2024. http://www.theses.fr/2024DUNK0698.
This thesis explores the technological development of a spectroscopic experiment in the submillimeter range, also known as Terahertz (THz). This spectral band stands out for its ability to precisely resolve molecular doublets, enabling clear and precise identification of complex gas mixtures, even when other wavelengths might fail.Although the THz region offers exceptional resolving power, spectrometers operating in this region often face sensitivity challenges due to the development of technology in this band. Thanks to an innovative approach, we have implemented the first Cavity Ring-Down Spectroscopy (CRDS) experiment capable of quantifying compounds to ppb precision. The study is concentrated between 550 GHz and 650 GHz, a window of the THz spectrum that not only offers unrivalled resolution and molecular sensitivity, but also possesses the ability to penetrate non-conducting materials while being non-ionizing. These properties position this technology at the cutting edge of analysis tools, promising a plethora of applications, from fundamental research to industrial applications
Marcinkiewicz, Michal. "Terahertz Spectroscopy of Topological Phase Transitions in HgCdTe-based systems." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS068/document.
This thesis presents an investigation of different topological phases in mercury-cadmium-telluride (HgCdTe or MCT) based heterostructures. These solid state systems are indeed a perfect playground to study topological states, as their band structure can be easily varied from inverted to non-inverted, by changing internal or external parameters.If a system has an inverted band ordering, its electronic structure has a non-trivial topology. One cannot change its topological order without closing the band gap, which is inevitably accompanied with the appearance of massless particles in the bulk. A system, that has an inverted band structure and a finite gap in which the Fermi level is positioned, is called a topological insulator. These novel materials are insulators in the bulk, but host gapless metallic states with linear dispersion relation at boundaries, protected against disorder and backscattering on non-magnetic impurities. These states arise at the interfaces between materials characterized by a different topological order. A 2D topological insulator is thus characterized by a set of 1D spin-polarized channels of conductance at the edges, while a 3D topological insulator supports spin-polarized 2D Dirac fermions on its surfaces.The 2D and 3D massless fermions have already been demonstrated experimentally in HgCdTe-based heterostructures. However, the topological phase transitions during which the massless particles appear remain barely explored. The HgCdTe band structure can be tuned from inverted to non-inverted using chemical composition, pressure, temperature, or quantum confinement. These parameters therefore allow to probe the system in the vicinity of different topological phase transitions. In this thesis, the use of temperature as continuous band gap tuning parameter allows to study the appearance and the parameters of semi-relativistic 2D Dirac and 3D Kane fermions emerging at the points of phase transitions.The systems investigated were Hg$_{1-x}$Cd$_x$Te bulk systems and HgTe/CdTe quantum wells characterized by an inverted and regular band order, and strained HgTe films which can be considered as 3D topological insulators with a residual quantum confinement. All these systems exhibit topological properties, and the experimental results are interpreted according to theoretical predictions based on the Kane model. This thesis is complemented by an overview and the preliminary results obtained on a different compound -- a InAs/GaSb broken-gap quantum well, which was also identified as a topological insulator. The structures were studied by means of terahertz and mid-infrared magneto-transmission spectroscopy in a specifically designed experimental system, in which temperature could be tuned in a broad range
Colarusso, Pina. "Selected projects in gas-phase spectroscopy." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq22196.pdf.
Puskar, Ljiljana. "Gas phase ligand field photofragmentation spectroscopy." Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394258.
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.
Faulk, James Donald. "Spectroscopy and photodynamics of gas phase ions." Case Western Reserve University School of Graduate Studies / OhioLINK, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1055789262.
Zhang, Keqing. "Infrared spectroscopy of molecules in the gas phase." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21402.pdf.
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.
O'Brien, Leah Christine. "Laser and Fourier transform spectroscopy of gas phase molecules." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184305.
Álvarez, Ruiz Jesús. "Synchrotron radiation induced fluorescence spectroscopy of gas phase molecules." Doctoral thesis, KTH, Physics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-43.
A new experimental set-up for gas phase fluorescence studies using synchrotron radiation has been designed and constructed to perform simultaneously total and dispersed fluorescence measurements.
Neutral photodissociation of CO has been investigated after excitation with 19-26 eV photons. Fluorescence from 3p 3P, 3p 3S and 3p 1D excited states in carbon was recorded and interpreted by ab initio calculations. The population and dissociation of states belonging to the C and D Rydberg series in CO seem to explain the production of the observed triplet states but not the 3p 1D state.
Neutral photodissociation of NO is reported in the 17-26 eV energy range. No known molecular states can account for the collected data. New information regarding the precursor states of the observed neutral dissociation is provided by ab initio calculations.
Autoionization of superexcited states in molecular nitrogen is evidenced by strong deviations of the Franck-Condon ratio in the fluorescence of the N2+ B state. Ab initio calculations predict the existence of autoionizing-excited states that may account for some of the observed structures in the 20-46 eV energy range.
Selective molecular fluorescence from the npó1Óu+ and npð 1Ðu (n=3-7) Rydberg levels to the E,F 1Óg+ state in H2 was recorded and rotationally analyzed. Vibrational levels of the E,F 1Óg+ state (vEF =0,1,3,6-10) are determined. The predissociation of npð 1Ð+ levels is observed in agreement with the literature.
Fragmentation of SF6 was investigated after excitation with 25–80 eV photons. Dispersed fluorescence measurements reveal the emission of S, S+, F and F+ excited atoms. These fragments are produced after single, double and triple excitations as well as direct ionizations and shake-ups in SF6.
Photoabsorption and fluorescence yield have been measured in SF5CF3 using 10-30eV photons. The photoabsorption spectrum can be explained in terms of its similarities to those of the SF6 and CF4 molecules. The dispersed and un-dispersed fluorescence resemble those of the CF3X family. Several features suggest the migration of an F atom across the S-C bond that fragments the molecule producing excited CF4.
Doubly excited states of H2 have been investigated in the range of 26-60 eV by monitoring Balmer á emission. The experimental data show the already known emission correlated with the fragmentation of the Q1 and Q2 states, and new features which could be attributed to dissociative photoionization and higher lying doubly excited states Qn (n>2) of the hydrogen molecule
Cockett, Martin Charles Roy. "Some studies in gas-phase photoelectron and chemielectron spectroscopy." Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.255760.
Haggerston, Darren. "Some studies in the gas phase using photoelectron spectroscopy." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262155.
Cooper, Graham Alastair. "Spectroscopy and imaging of gas-phase transition metal clusters." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:9db3727c-4246-4d39-95b3-83936265dfad.
Baran, Stuart George. "Gas-phase detection methods using diode lasers." Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:43e8ec07-9e1a-4060-bc8b-be75c8565600.
Newnham, David A. "High vibrational overtone spectroscopy." Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278081.
Liu, Zhuan. "Infrared diode laser absorption spectroscopy of gas phase molecular ions." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627231.
Knox, David Andrew. "High resolution gas phase spectroscopy at solid/solid interfacial regions." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/high-resolution-gas-phase-spectroscopy-at-solid--solid-interfacial-regions(b5dfd0d0-7c6a-4b50-ad78-39c10c33b3ac).html.
Morse, Jennifer Marie. "Electronic Effects of Solvation: A Comparison of Gas-Phase and Condensed-Phase Photoelectron Spectroscopy." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/194130.
Cramb, David Thomas. "Molecular spectroscopy of ionic and neutral species in the gas phase." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30664.
Science, Faculty of
Chemistry, Department of
Graduate
Forthomme, Damien. "High Resolution Laser Spectroscopy Of Selected Molecules In The Gas Phase." Thesis, Fredericton: University of New Brunswick, 2011. http://hdl.handle.net/1882/35387.
Ali, Sahangir. "Gas phase vacuum-ultraviolet (vuv) spectroscopy of small halogenated polyatomic molecules." Thesis, University of Birmingham, 2007. http://etheses.bham.ac.uk//id/eprint/897/.
Borkar, Sampada N. "Very accurate gas-phase thermochemistry through photoelectron photoion coincidence (PEPICO) spectroscopy." Scholarly Commons, 2013. https://scholarlycommons.pacific.edu/uop_etds/144.
Villano, Stephanie M. "Gas-phase negative ion chemistry: Photoelectron spectroscopy, reactivity, and thermochemical studies." 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:3337158.
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.
Haverd, Vanessa. "Time resolved Fourier transform infrared emission studies of gas phase kinetics and dynamics." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270047.
Dookwah-Roberts, Venus Maria Christina. "Spectroscopy and Kinetics of Weakly Bound Gas-Phase Adducts of Atmospheric Interest." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24743.
Zimmermann, Nina Tamara [Verfasser]. "Manganese oxide cluster : Gas phase reactions and IR spectroscopy / Nina Tamara Zimmermann." Ulm : Universität Ulm, 2021. http://d-nb.info/1231916494/34.
Li, Kexin. "GAS PHASE MICROWAVE SPECTROSCOPY AND INSTRUMENT DEVELOPMENT ON A DOUBLE RESONANCE EXPERIMENT." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/618749.
Weichmann, Marissa L., Xiaowei Song, Matias R. Fagiani, Sreekanta Debnath, Sandy Gewinner, Wieland Schöllkopf, Daniel M. Neumark, and Knut Roger Asmis. "Gas phase vibrational spectroscopy of cold (TiO2)−n (n = 3–8) clusters." AIP Publishing, 2016. https://ul.qucosa.de/id/qucosa%3A21255.
Dookwah-Roberts, Venus Maria Christina. "Spectroscopy and kinetics of weakly bound gas-phase ddducts of atmospheric interest." Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24743.
Committee Chair: Wine, Paul; Committee Member: Huey, Greg; Committee Member: Nenes, Athanasios; Committee Member: Weber, Rodney; Committee Member: Whetten, Robert.
Aliwell, Simon Richard. "Measurement of atmospheric trace gases by absorption spectroscopy." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388668.
Briggs, Ronald D. "High-resolution nonlinear laser wave-mixing spectroscopy for gas-phase environmental and atmospheric studies /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2004. http://wwwlib.umi.com/cr/ucsd/fullcit?p3112972.
Daly, Adam Michael. "Gas Phase Structures and Molecular Constants of Dimers and Molecules Determined using Microwave Spectroscopy." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/195595.
Ashman, A. S. "Laser spectroscopy of molecular ions in an Ion Cyclotron Resonance apparatus." Thesis, University of Reading, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234408.
Gause, Oliver [Verfasser]. "Femtosecond spectroscopy and coherent control on flavins in the gas phase / Oliver Gause." Berlin : Freie Universität Berlin, 2012. http://d-nb.info/1027151558/34.
Medvecz, Patrick J. "Spectroscopic evaluation of the gas phase above a burning black liquor char bed." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/5759.
Hansford, Graeme Mark. "Diode laser infrared spectroscopy of jet-cooled polyatomic molecules." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321031.
Rius, i. Riu Jaume. "Gas phase molecular relaxation probed by synchrotron radiation experiments." Doctoral thesis, KTH, Physics, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3411.
This thesis presents experimental studies of gas phasemolecular relaxation after excitation with synchrotron photonsin the 15-35 eV and in the 70-350 eV regions.
In the 15-35 eV region, molecular relaxation by neutraldissociation processes and non
Franck-Condon effects in N2 and O2 molecules have beenstudied by means of dispersed fluorescence and photoelectronspectroscopy experimental techniques, respectively. From thedispersed fluorescence data, excitation functions for themeasured atomic fluorescence spectra have been obtained. Fromthe recorded photoelectron spectra vibrational branching ratioshave been produced. The results obtained reveal that Rydbergseries and singly and doubly excited valence states of theappropriate symmetry energetically accessible in the studiedregion and interactions between themaccount for most of theobserved effects in these two type of experiments.
In the 70-350 eV range, molecular relaxation processesresulting in fragmentation of CD4 and SF6 after absorption ofsynchrotron light have been studied by energy resolved electronion coincidence technique using a multicoincidence experimentalstation developed by our group during the last five years forsuch type of experiments. The coincidence measurements yieldedmass spectra from which information about the kinematics of thedetected fragments has been deduced by means of Monte Carlosimulations of the experimental peak shapes. The obtainedresults show completely different dissociation patternsdepending on the molecular electronic states studied. Thesepatterns reflect the bonding properties of the excited orbitalsand they permit the description and in some cases theidentification of the different molecular relaxation pathwaysobserved. The achievements presented in this thesis exemplifythe potential of the multicoincidence station used in thereported experiments.
Esposito, Anthony Paul. "Resonance Raman studies of halooxide photochemistry in the gas and condensed phase /." Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/8616.
Raja, Ibrahim Raja Kamarulzaman Kamarulzaman. "Mid-infrared diagnostics of the gas phase in non-thermal plasma applications." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/midinfrared-diagnostics-of-the-gasphase-in-nonthermal-plasmaapplications(3b684a12-78fa-4d9b-94d2-0f066b7a828e).html.
Schubert, Franziska [Verfasser]. "Conformational equilibria and spectroscopy of gas-phase homologous peptides from first principles / Franziska Schubert." Berlin : Freie Universität Berlin, 2014. http://d-nb.info/106294917X/34.
Butcher, V. A. "Studies of some reactive intermediates in the gas-phase by ultra-violet photoelectron spectroscopy." Thesis, University of Southampton, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381210.
Qian, Haibo. "Diode laser spectroscopy of free radicals and other transient molecules in the gas phase." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627118.
Smith, Zachary Michael. "Computational Investigations of the Structure and Spectroscopy of Small Biomolecules in the Gas Phase." W&M ScholarWorks, 2018. https://scholarworks.wm.edu/etd/1550153898.
Culberson, Lori. "Molecular Electronic Structure via Photoelectron Imaging Spectroscopy." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/301677.
Hanni, M. (Matti). "Static and dynamic NMR properties of gas-phase xenon." Doctoral thesis, University of Oulu, 2011. http://urn.fi/urn:isbn:9789514294570.
Kaposta, Eva Cristina. "Gas phase infrared photodissociation spectroscopy mass selected cluster ions strong hydrogen bonds and vanadium oxides /." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=978049314.
Fagiani, Matias Ruben [Verfasser]. "Cryogenetic ion vibrational spectroscopy of gas-phase clusters : Structure, Anharmonicity and Fluxionality / Matias Ruben Fagiani." Berlin : Freie Universität Berlin, 2017. http://d-nb.info/113162937X/34.