Atomic and molecular low-n Rydberg states in supercritical fluids
Item
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Title
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Atomic and molecular low-n Rydberg states in supercritical fluids
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Identifier
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d_2009_2013:d102abc36b47:10117
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identifier
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10216
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Creator
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Li, Luxi,
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Contributor
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Cherice M. Evans
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Date
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2009
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Language
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English
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Publisher
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City University of New York.
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Subject
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Physical chemistry | critical point effect | Low-n Rydberg states | supercritical fluid | VUV absorption
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Abstract
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The structure of low-n Rydberg states doped into supercritical fluids represents an important probe to investigate solvation effects, especially near the solvent (or perturber) critical point. We have investigated the solvation of excited atomic and molecular dopants in various perturbing fluids (both atomic and molecular). This systematic study was performed from low perturber number densities to the density of the triple point liquid, at both non-critical temperatures and on an isotherm near the critical isotherm. Dopant low- n Rydberg states were investigated using vacuum ultraviolet photoabsorption spectroscopy. The absorption spectra of these states were then simulated using a semi-classical statistical line shape function. With accurate line shape simulations, the perturber induced energy shift of the primary transition was obtained using a standard moment analysis.;The moment analysis indicated that the dopant low-n Rydberg state energy blue shifts as a function of perturber number density without a significant temperature effect (except near the critical isotherm). A significant critical point effect was observed in all dopant/pertuber systems investigated here. This critical point effect is caused by a large increase in the dopant/perturber radial distribution function near the critical temperature of the perturber. Since the first perturber solvent shell shields the cationic core, the binding energy of the optical electron decreases. This acts to increase the dopant low-n Rydberg state excitation energy. However, the overall blue shift and critical point effect varies from atomic to molecular perturber systems due to the structure of the perturber. These differences are also discussed in more detail in this work.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Chemistry
