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Title of Thesis Or Dissertation, Worded Exactly As It PRESSURE BROADENING AND PRESSURE SHIFT OF DIATOMIC IODINE AT 675 NM by ERICH N. WOLF A DISSERTATION Presented to the Department of Chemistry and the Graduate School of the University of Oregon in partial fulfillment of the requirements for the degree of Doctor of Philosophy June 2009 ii “Pressure Broadening and Pressure Shift of Diatomic Iodine at 675 nm,” a dissertation prepared by Erich N. Wolf in partial fulfillment of the requirements for the Doctor of Philosophy degree in the Department of Chemistry. This dissertation has been approved and accepted by: ____________________________________________________________ Dr. David Herrick, Chair of the Examining Committee ________________________________________ Date Committee in Charge: Dr. David R. Herrick, Chair Dr. John L. Hardwick Dr. Michael G. Raymer Dr. Jeffrey A. Cina Dr. David R. Tyler Accepted by: ____________________________________________________________ Dean of the Graduate School Erich N. Wolf / Pressure Broadening and Pressure Shift of I2 at 675 nm / June 2009 iii An Abstract of the Dissertation of Erich N. Wolf for the degree of Doctor of Philosophy in the Department of Chemistry to be taken June 2009 Title: PRESSURE BROADENING AND PRESSURE SHIFT OF DIATOMIC IODINE AT 675 NM Approved: _______________________________________________ Dr. David Herrick, Chair of the Examining Committee 127 Doppler-limited, steady-state, linear absorption spectra of I2 (diatomic iodine) near 675 nm were recorded with an internally-referenced wavelength modulation spectrometer, built around a free-running diode laser using phase-sensitive detection, and capable of exceeding the signal-to-noise limit imposed by the 12-bit data acquisition system. Observed I2 lines were accounted for by published spectroscopic constants. Pressure broadening and pressure shift coefficients were determined respectively from the line-widths and line-center shifts as a function of buffer gas pressure, which were determined from nonlinear regression analysis of observed line shapes against a Gaussian-Lorentzian convolution line shape model. This model included a linear superposition of the I2 hyperfine structure based on changes in the nuclear electric quadrupole coupling constant. Room temperature (292 K) values of these coefficients −1 were determined for six unblended I2 lines in the region 14,817.95 to 14,819.45 cm for Erich N. Wolf / Pressure Broadening and Pressure Shift of I2 at 675 nm / June 2009 iv each of the following buffer gases: the atoms He, Ne, Ar, Kr, and Xe; and the molecules H2, D2, N2, CO2, N2O, air, and H2O. These coefficients were also determined at one additional temperature (388 K) for He and CO2, and at two additional temperatures (348 and 388 K) for Ar. Elastic collision cross-sections were determined for all pressure broadening coefficients in this region. Room temperature values of these coefficients were also determined for several low-J I2 lines in the region 14,946.17 to 14,850.29 cm−1 for Ar. A line shape model, obtained from a first-order perturbation solution of the time-dependent Schrödinger equation for randomly occurring interactions between a two-level system and a buffer gas treated as step-function potentials, reveals a relationship between the ratio of pressure broadening to pressure shift coefficients and a change in the wave function phase-factor, interpreted as reflecting the “cause and effect” of state-changing events in the microscopic domain. Collision cross-sections determined from this model are interpreted as reflecting the inelastic nature of collision-induced state-changing events. A steady-state kinetic model for the two-level system compatible with the Beer-Lambert law reveals thermodynamic constraints on the ensemble-average state- changing rates and collision cross-sections, and leads to the proposal of a relationship between observed asymmetric line shapes and irreversibility in the microscopic domain. (The graduate school at the University of Oregon imposes a word limit [350 words] on dissertation abstracts so that the last paragraph of the abstract did not include Erich N. Wolf / Pressure Broadening and Pressure Shift of I2 at 675 nm / June 2009 v a passage akin to the following: A modified version of the Einstein A and B Coefficient model appropriate for linear absorption is offered [Section 2.11], one that is based on the mathematical operation of convolutions and allows for a derivation of the Beer-Lambert Law for the state-changing processes in the two-level model [stimulated absorption, stimulated emission, and spontaneous emission] for the case of steady-state dynamics in the microscopic domain. This model indicates that the rates for stimulated absorption and stimulated emission are not necessarily equal, which is tantamount to the B coefficients for stimulated absorption and stimulated emission not necessarily being equal. Furthermore, this model indicates that the collision cross-sections for stimulated absorption and stimulated emission are not equal. As well, with regard to the well documented appearance of asymmetric line shapes in high-resolution linear absorption spectra, it would have been mentioned that such features may be more fully consistent with the reality that the universe we live in [i.e. that there is no such thing as a perfectly isolated object] is more properly described by non-Hermitian Hamiltonians; in the context of the [non-degenerate] two-level model, the Hamiltonian that describes photon absorption is not the Hermitian conjugate of the Hamiltonian that describes photon emission. Apart from the foregoing addendum to the abstract, the inclusion of a footer on all pages of the dissertation indicating the author’s name, dissertation title, and year of submission of the dissertation, and inclusion of publications in the field of organometallic chemistry, this version of the dissertation is the one that was accepted by the graduate school at the University of Oregon.) Erich N. Wolf / Pressure Broadening and Pressure Shift of I2 at 675 nm / June 2009 vi CURRICULUM VITAE NAME OF AUTHOR: Erich N. Wolf GRADUATE AND UNDERGRADUATE SCHOOLS ATTENDED: University of Oregon California State University, Northridge DEGREES AWARDED: Doctor of Philosophy in Chemistry, 2009, University of Oregon Bachelor of Science in Physics, 1993, California State University, Northridge AREAS OF SPECIAL INTEREST: Chemical Physics, Quantum Electrodynamics, Statistical Physics, Thermodynamics, Solid State Physics, Classical Physics, Astrophysics and Cosmology, and Mathematics Atomic and Molecular Spectroscopy Inorganic and Organometallic Chemistry and Catalysis Materials and Properties of Materials PROFESSIONAL EXPERIENCE: Research Assistant, Department of Chemistry, University of Oregon, Eugene, June 2001 − September 2007 Teaching Assistant, Undergraduate Physical Chemistry Laboratory, Department of Chemistry, University of Oregon, Eugene, September 2001 − June 2002, September 2003 − June 2004, and September 2005 − June 2006 Research Assistant, Department of Chemistry, California State University, Northridge, March 1988 − June 1992 Erich N. Wolf / Pressure Broadening and Pressure Shift of I2 at 675 nm / June 2009 vii PUBLICATIONS: Spectroscopy: Arteaga, S. W., C. M. Bejger, J. L. Gerecke, J. L. Hardwick, Z. T. Martin, J. Mayo, E. A. McIlhattan, J.-M. F. Moreau, M. J. Pilkenton, M. J. Polston, B. T. Robertson, and E. N. Wolf. “Line Broadening and Shift Coefficients of Acetylene at 1550 nm.” Journal of Molecular Spectroscopy 243 (2007): 253-266. Hardwick, J. L., Z. T. Martin, M. J. Pilkenton, and E. N. Wolf. “Diode Laser Absorption Spectra of H12C13CD and H13C12CD at 6500 cm−1.” Journal of Molecular Spectroscopy 243 (2007): 10-15. Hardwick, J. L., Z. T. Martin, E. A. Schoene, V. Tyng, and E. N. Wolf. “Diode Laser −1 Absorption Spectrum of Cold Bands of C2HD at 6500 cm .” Journal of Molecular Spectroscopy 239 (2006): 208-215. Eng, J. A., J. L. Hardwick, J. A. Raasch, and E. N. Wolf. “Diode Laser Wavelength Modulated Spectroscopy of I2 at 675 nm.” Spectrochimica Acta Part A 60 (2004): 3413-3419. Organometallic Chemistry: Rosenberg E., S. E. Kabir, L. Milone, R. Gobetto, D. Osella, M. Ravera, T. McPhillips, M. W. Day, D. Carlot, S. Hajela, E. Wolf, K. I. Hardcastle. “Comparative Reactivity of Triruthenium and Triosmium μ 3-η 2-Imidoyls. 2. Reactions with Alkynes.” Organometallics 16 (1997): 2674-2681. Rosenberg E., L. Milone, R. Gobetto, D. Osella, K. I. Hardcastle, S. Hajela, K. Moizeau, M. Day, E. Wolf, D. Espitia. “Comparative Reactivity of Triruthenium and Triosmium μ 3-η 2-Imidoyls. 1. Dynamics and Reactions with Carbon Monoxide, Phosphine, and Isocyanide.” Organometallics 16 (1997): 2665-2673. Rosenberg E., S. E. Kabir, M. Day, K. I. Hardcastle, E. Wolf, T. McPhillips. “Chemistry of Nitrogen Donors with μ 3-Imidoyl Triosmium Clusters: Dynamics of a Monometallic Site in a Trimetallic Cluster.” Organometallics 14 (1995): 721-733. Erich N. Wolf / Pressure Broadening and Pressure Shift of I2 at 675 nm / June 2009 viii Rosenberg E., M. Day, W. Freeman, K. I. Hardcastle, M. Isomaki, S. E. Kabir, T. McPhillips, L. G. Scott, E. Wolf; “Comparative study of the reactions of diazomethane with μ 3-imidoyl and μ 3-butyne trinuclear clusters”, Organometallics 11 (1992): 3376-3384. Rosenberg E., M. W. Day, S. Hajela, S. E. Kabir, M. Irving, T. McPhillips, E. Wolf, K. I. Hardcastle, L. Milone, et al.; “Reactions of tertiary amines with trinuclear clusters. 3. Reactions of N-methylpyrrolidine with Ru3(CO)12 and Os3(CO)10(CH3CN)2.” Organometallics 10 (1991): 2743-2751.
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