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Molecular beam laser stark spectroscopy of highly vibrationally excited moleculesStoer, Marcell 04 August 2017 (has links)
The Stark field perturbed spectra of near infrared vibrational
overtones of hydrogen fluoride and acetylene have been measured with a
high resolution molecular beam laser spectrometer. A high performance
laser power build-up cavity (optical resonator) was constructed to
measured the weak ro-vibrational transitions of the v₂ + 3v₃ vibrational
combination band of acetylene. The measured gain of the build-up
cavity was found to be at least 300 out of a potential 2000. The
primary reason for the lower than expected gain was attributed to
losses induced by the extreme heat build-up on the mirror surfaces.
The electric dipole moment for the v = 3 vibrational overtone of
hydrogen fluoride was determined to be 1.9614 ± 0.0021 Debye. This
result was compared with predictions from the available theoretical
models and some theoretical constants were revised based on the
current contribution to dipole moment function of hydrogen fluoride.
The Stark field perturbed spectra of the v₁ + 3v₃ and v₂ + 3v₃
vibrational combination bands of acetylene were analysed for their
polarisability tensors. In order to complete the study, the ground
electronic state static polarisability and anisotropy of the
polarisability were also determined. They were found to be 3.96A³ and
1.071 ± 0.014A³, respectively. The |1030⁰0⁰> state (v₁ + 3v₃) was
observed to be coupled with the |0040⁰0⁰> infrared forbidden state (4v₃)
in the presence of the Stark electric field. The resultant analysis
produced values of 4.62 ± 0.09A³ for the polarisability and 1.15 ±
0.03A³ for the polarisability anisotropy of the |1030⁰0⁰> state. The
difference in energy between |1030⁰0⁰> and |0040⁰0⁰> was determined to be
4.133 cm⁻¹, which compares well with local mode calculations.
The measurements of the v₂ + 3v₃ band indicated that the |0130⁰0⁰> state
was strongly coupled with another infrared allowed, unidentified
(rogue), state in the absence of the Stark field as well as with the
infrared forbidden, |1120⁰0⁰> state in the presence of the Stark field.
The previously unobserved J = 5 ← 4 transition of the infrared allowed
rogue state was recorded here for the first time. The Stark field
perturbed spectra of the R(3) and R(5) ro-vibrational transitions of
the v₂ + 3v₃ band also showed evidence of rogue transitions. The ensuing
analysis determined that the |0130°0°) state has a polarisability of
3.5 ± 0.3A³ and a polarisability anisotropy of 5.6 ± 1.8A³. The Stark
field perturbed spectra of the R(3) and R(5) transitions were fit to a
non-crossing model and the energy levels of the rogue J = 4 and J = 6
states were determined. The energy level difference between |0130°0°)
and |1120°0°) was determined to be -11.88±0.22 cm⁻¹. This does not
compare well with local mode calculations and it is possible that the
perturbations due to the presence of the rogue state impeded the
accurate determination of the energy level difference. The identity of
the rogue vibrational state could not be determined from the data
presented in this thesis alone. However, collaborative work with
another research group suggests that the rogue vibrational state is |0306°3¹) (see Chapter 7). / Graduate
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X-ray spectroscopy of organic materialsWilks, Regan G. 29 June 2009
The radiation-induced decomposition of glycine is studied using a combination of Near Edge X-ray Absorption Fine Structure (NEXAFS) measurements and density functional theory calculations. Principal Component Analysis was used to determine the number of distinct molecules that were needed to explain the observed changes in the measured spectra, and the emerging absorption features are assigned to various product molecules through comparison with simulated spectra of several model compounds. It is clear from the experiment that the major effect of soft X-ray irradiation is the fragmentation of the molecule, primarily at the carbonyl sites. Peptide formation is shown to occur under irradiation; a condensation reaction initiated by the removal of a carbonyl oxygen is the proposed mechanism. This study utilizes a novel approach to the study of radiation damage that can occur during measurements, and suggests that it may be possible to use simulated model spectra to correct for these effects in measured spectra.<p>
A study of oligothiophene-based molecular semiconductor materials with potential applications in light-emitting and photovoltaic devices is undertaken. Angle-resolved NEXAFS measurements of the star-shaped 4(HPBT) molecules on an amorphous indium surface show a strong dichroic signal indicating a well-ordered, uniformly upright arrangement of planar molecules. The X-ray excited optical luminescence (XEOL) measurements showed several sharp features associated with vibronic splitting of the LUMO-HOMO luminescent transition. The HOMO-LUMO gap determined from the XEOL measurements is 2.28 eV; this value is in agreement with previously published optical measurements as well as with the value that is estimated from the combination of NEXAFS and X-ray emission spectroscopy (XES) measurements. Films formed from blended solutions of 4(HPBT) and the hole-transporting molecular semiconductor PCBM are shown to form a bilayer structure with the PCBM adjacent to the substrate. Annealing causes desorption of the 4(HPBT) from the surface.
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X-ray spectroscopy of organic materialsWilks, Regan G. 29 June 2009 (has links)
The radiation-induced decomposition of glycine is studied using a combination of Near Edge X-ray Absorption Fine Structure (NEXAFS) measurements and density functional theory calculations. Principal Component Analysis was used to determine the number of distinct molecules that were needed to explain the observed changes in the measured spectra, and the emerging absorption features are assigned to various product molecules through comparison with simulated spectra of several model compounds. It is clear from the experiment that the major effect of soft X-ray irradiation is the fragmentation of the molecule, primarily at the carbonyl sites. Peptide formation is shown to occur under irradiation; a condensation reaction initiated by the removal of a carbonyl oxygen is the proposed mechanism. This study utilizes a novel approach to the study of radiation damage that can occur during measurements, and suggests that it may be possible to use simulated model spectra to correct for these effects in measured spectra.<p>
A study of oligothiophene-based molecular semiconductor materials with potential applications in light-emitting and photovoltaic devices is undertaken. Angle-resolved NEXAFS measurements of the star-shaped 4(HPBT) molecules on an amorphous indium surface show a strong dichroic signal indicating a well-ordered, uniformly upright arrangement of planar molecules. The X-ray excited optical luminescence (XEOL) measurements showed several sharp features associated with vibronic splitting of the LUMO-HOMO luminescent transition. The HOMO-LUMO gap determined from the XEOL measurements is 2.28 eV; this value is in agreement with previously published optical measurements as well as with the value that is estimated from the combination of NEXAFS and X-ray emission spectroscopy (XES) measurements. Films formed from blended solutions of 4(HPBT) and the hole-transporting molecular semiconductor PCBM are shown to form a bilayer structure with the PCBM adjacent to the substrate. Annealing causes desorption of the 4(HPBT) from the surface.
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Reaction dynamics of high temperature systems : I. O ̄⁺ H₂ products II. O ̄⁺ H₂ productsFountain, Tina Lynn 05 1900 (has links)
No description available.
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A theoretical study of the vibrational excitation of diatomic moleculesClark, Alan Peter January 1974 (has links)
Exact quantum mechanical-vibrational transition probabilities are calculated for a collinear atom-diatomic molecule collision, using the real reactance matrix K. Both the Morse and harmonic binding potentials are considered. It is found that the discrepancy between the transition probabilities for these binding potentials may be large, depending on the collision parameters m and α; the discrepancy increases as m becomes large and decreases as α becomes large. Large Morse well depths (characterised by large values Of De) do not necessarily imply agreement between the transition probabilities of the two oscillators. Anharmonicity will be important in most collisions. The validity of several approximate theories when applied to this problem is investigated, It is found that the revised first order distorted wave approximation of Mies (1964a), and hence the revised first order perturbation theory approximation (Mies 1964b), are valid providing the reduced mass m is not too large or the collision too strong. Based on these investigations the one-dimensional form of the correspondence principle for strongly coupled states (Percival and Richards 1970a) is modified to include, approximately, the perturbation of the bound system. The modified theory is tested on the system of a harmonic oscillator, perturbed by a potential q2F(t) and excellent agreement with the exact quantum mechanical solution is obtained. The theory is then applied to the collinear atom-diatomic molecule collision, with a Morse molecular binding potential. For a large range of collision parameters, the results are in good agreement with the exact quantum mechanical transition probabilities, even for low order transitions. The modified correspondence principle is shown to have a larger range of validity than the revised first order perturbation theory approximation of Mies (1964b)to which it reduces in the weak perturbation limit.
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TOF-SIMS measurements of elemental and molecular distributions in human hair /Kempson, Ivan Mark. Unknown Date (has links)
Thesis (PhD)--University of South Australia, 2003.
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Spectral and orbital based analyses of interactions in some biomolecules /Saha, Saumitra. January 2008 (has links)
Thesis (Ph. D.)--Swinburne University of Technology, Centre for Molecular Simulation - 2008. / Dissertation submitted in fulfilment of requirements for the degree Doctor of Philosophy, Centre for Molecular Simulation, Swinburne University of Technology, 2008. Typescript. Includes bibliographical references (p. 188-218).
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Pulsed laser and diode laser spectroscopy of small molecules /Das, Palash Kusum Parijat January 1980 (has links)
No description available.
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Molecular ion recoil spectroscopy applied to methaneNeedham, Vincent. January 1984 (has links)
Call number: LD2668 .T4 1984 N43 / Master of Science
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DETERMINATION OF HYDROXYL RADICAL CONCENTRATION PROFILES IN THE LAMINAR, OPPOSED-JET DIFFUSION FLAME.Anderson, William E. (William Edward) January 1984 (has links)
No description available.
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