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 Title: Sonoluminescence as a probe of acoustic cavitation Author(s): House, Kathleen Ann Doctoral Committee Chair(s): Kenneth S. Suslick Department / Program: Chemistry Discipline: Chemistry Degree Granting Institution: University of Illinois at Urbana-Champaign Degree: Ph.D. Genre: Dissertation Subject(s): Chemistry, Inorganic Abstract: Sonoluminescence is defined as the light emitted when a liquid is irradiated with ultrasound. Sonoluminescence is observed during ultrasonic irradiation of chromium, iron, molybdenum, and tungsten carbonyl solutions. The observed spectral lines correspond to atomic emission from the metal atoms. The intensity of sonoluminescence from Cr(CO)$\sb6$ was studied as a function of dissolved gases to determine the effect of thermal conductivity and $\gamma$ (C$\sb{\rm p}$/C$\sb{\rm v}$) on cavitational conditions. As predicted by thermal theories of sonoluminescence, the intensity of excited-state chromium emission decreases with increasing thermal conductivity of the noble gas, and the intensity of sonoluminescence from silicone oil solutions of Cr(CO)$\sb6$ was found to decrease with decreasing 1/($\gamma-$1).The sonoluminescence linewidth from Cr(CO)$\sb6$ is much broader than the linewidth from a typical gas-phase hollow cathode lamp spectrum. By assuming collisional deactivation of chromium by argon and using the Heisenberg Uncertainty Principle, the effective lifetime of the emitting species (Cr$\sp\*$) before collisional deactivation was calculated to be 0.20 $\pm$ 0.02 picoseconds.From the lifetime, local fluid densities following cavitational collapse can be calculated using the equation: N$\sp{-1}$ = $2\tau\sigma\sb{12}\sp2$ ($2\pi$RT(m$\sb1$ + m$\sb2$)/(m$\sb1$m$\sb2$)) $\sp{1/2}$ where N is the density, $\tau$ is the lifetime, $\sigma\sb{12}\sp2$ is the cross-section of the colliding atoms, and T is the temperature of the cavitation event. The local fluid density during chromium atom emission was calculated to be 0.15 $\pm$ 0.01 g/cm$\sp3$.From the lifetime and density it is possible, by using the Virial Equation of State, to calculate the effective pressure in the region of the emitting chromium atoms.$$\rm P = RT\rho/m\ \lbrack 1 + B\sb{T}\rho/m + C\sb{T}\rho\sp2/m\sp2 + \...\rbrack$$Using this equation, the effective pressure during sonoluminescence in the region of the excited-state chromium atoms was calculated to be 1700 $\pm$ 110 atmospheres. This result represents the first experimental determination of the pressure of the cavitation event.Sonoluminescence from seawater was studied to determine the effect of organic particulate matter on the observed intensity. Sonoluminescence from saltwater is characterized by emission from excited-state sodium atoms. There was no difference in intensity within experimental error for saltwater samples which were taken from surface or deepwater or were filtered or unfiltered. Issue Date: 1994 Type: Text Language: English URI: http://hdl.handle.net/2142/22517 Rights Information: Copyright 1994 House, Kathleen Ann Date Available in IDEALS: 2011-05-07 Identifier in Online Catalog: AAI9512399 OCLC Identifier: (UMI)AAI9512399
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