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Showing 1 to 20 of 56 for “"molecular ions"”.
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Rotational Spectroscopy of Molecular Ions
Made available in DSpace on 2014-12-13T20:10:47Z (GMT). No. of bitstreams: 1 8009019.pdf: 4354821 bytes, checksum: 91befa8e421b9008f874b81936648543 (MD5) Previous issue date: 1979
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Internal Excitations of Stored Triatomic Hydrogen Molecular Ions
The triatomic hydrogen molecular ion H3+ is the simplest polyatomic molecule, besides its fundamental importance for quantum chemistry, it is one of the cornerstones of molecular processes in interstellar clouds. The dissociative electron recombination (DR) of H3+ is much studied, but still subject …
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Laser spectroscopy of molecular ions in an ion beam
… ion beam is overlapped by a laser beam and the ions are Doppler-tuned into resonance. The experimental apparatus is suitable for the study of both positive and negative ions. Resonant transitions are reported in C{dollar}\sb2\sp{-}{dollar} and in CO{dollar}\sp{+}{dollar}. In …
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Inelastic collisions and recombination between electrons and molecular ions
Inelastic collisions between molecular ions and slow electrons play an important role in naturally occurring ionized media and involve interesting interaction mechanisms which are also under intense theoretical study. Several experiments focused on the collision of small molecular ions with …
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New techniques for sub-Doppler spectroscopy of molecular ions
… high-resolution sub-Doppler spectroscopy of molecular ions in the laboratory. Molecular ions are of interest to a variety of fields, from astrochemistry to fundamental physics to the study of chemical reactive intermediates. The limiting factor in developing a deeper understanding of many ion …
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Progress in sensitive mid-infrared spectroscopy of cooled molecular ions
The spectroscopic investigation of molecular ions is key to facilitating a better understanding of chemical and physical processes that occur both here on Earth and among distant stars. However, numerous challenges are encountered when attempting to study these highly reactive species in the …
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Atomic and molecular ions with photon resonators for quantum information science
… of laser-atom interaction, systems of trapped ions offer a promising platform for the realization of fault-tolerant quantum information processing (QIP). Much progress with single atomic and molecular ion qubits has been made both in theory and experiment on the fundamental building blocks for …
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Study of Plasmon Resonances in Single Photoionization of Carbon Fullerene Molecular Ions
Beams of carbon fullerene ions containing 40 to 84 carbon atoms were irradiated by monochromatized synchrotron radiation at photon energies ranging from 18-70 eV at 0.5 eV intervals. Single photoionization was studied over this energy range using a merged-beams research endstation at the Advanced …
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Photodissociation of molecular ions and low-energy collisions of atoms and ions
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1993.
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Development of a sensitive mid-infrared spectrometer for the study of cooled molecular ions
The study of molecular ions is relevant to many areas of scientific interest. Mid-infrared laser spectroscopy functions as a useful tool for understanding the role of molecular ions in these areas. To this end, a broadly tunable mid-infrared difference frequency generation noise-immune …
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Chemical physics and astrochemistry of H3+ and sub Doppler mid infrared spectroscopy of molecular ions
Molecular ions are known to be key reactive intermediates in interstellar environments, and H3+ in particular is responsible for initiating a network of chemical reactions that ultimately results in the formation of the ~170 molecules detected so far in space. Yet fundamental questions about the …
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Sensitive and high-precision rovibrational spectroscopy of molecular ions relevant to astronomical and quantum chemistry
High-precision spectroscopy of molecular ions has enabled new discoveries in astronomy and provided valuable benchmarks for ab initio calculations of molecular structure. Astronomers and theorists require accurate and precise laboratory measurements of rotational and rovibrational transition …
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Experimental and theoretical investigations of molecular ions by spectroscopy as well as ion mobility and mass spectrometry
… high resolution spectrograph and various combinations of IM and mass spectrometry. The novel high resolution 2D spectrograph facilitates spectroscopic resolutions in the range of commercial echelle spectrographs. The lowest full width at half maximum of a peak achieved was 25 pm. The 2D …
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Design, construction, and characterization of an ultra-sensitive, high-precision fast ion-beam spectrometer for the study of molecular ions
… spectrometer to record the absorption spectra of molecular ions. It is the first work to use the noise immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) technique in conjunction with a fast ion beam. Additionally, it is the first work outlining direct electronic …
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BINDING ENERGIES AND SOLVATION OF ORGANIC MOLECULAR IONS, REACTIONS OF TRANSITION METAL IONS WITH, AND PLASMA DISCHARGE IONIZATION OF MOLECULAR CLUSTERS
… and growth mechanisms of carbon-containing molecular ions with relevance to astrochemistry. Ion mobility mass spectrometry and DFT computations were used to investigate how a second nitrogen in the pyrimidine ring will affect the formation of a covalent bond between the benzene radical …
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High-accuracy and high-precision infrared spectroscopy of fundamental molecular ions using noise immune cavity enhanced optical heterodyne velocity modulation spectroscopy
… multi-body nature of the problem, and exact solutions are not achievable ab initio. Therefore, quantum mechanical calculations on molecules require approximate treatment in order to calculate quantities such as energy levels and spectra. High accuracy calculations that achieve ``spectroscopic …
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Cryogenic surface electrode ion traps with integrated superconducting microwave resonators for polar molecular ion spectroscopy
… experiments require precise control over the molecular internal degrees of freedom. There are few present proposals for trapping and cooling molecules. One proposal is based on confining neutral polar molecules in DC Stark shift traps, but this approach presents some issues. An attractive …
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A krypton VUV photoionization source for gas chromatography and mass spectrometry.
… photoionization mass spectrometer source, conditions can be created where molecular ions can be produced which do not undergo fragmentation. This effect can greatly simplify spectral interpretation in the case of either direct sample introduction or coelution from a chromatographic column. …
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The nuclear spin dependence of the reaction of H3+ with H2 and the proposed spectroscopic investigation of HO2+
High-resolution spectroscopy of molecular ions has been proven to be a difficult endeavor. Generating significant quantities of the desired ions and discriminating ions from neutrals are among some of the many difficulties surrounding the spectroscopic studies of these species. Despite these …
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Novel techniques for molecular ion spectroscopy in a discharge
… spectroscopic technique for the study of molecular ions; indeed, it has become the conventional technique. However, there are a number of limitations to velocity modulation in its conventional form. First, there is a background arising from r.f. pick-up or optical emission. Because the …
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