Kinetics and radiative processes of a xenon and iodine inductive RF discharge at low pressure
Barnes, Paul Nathan
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/20704
Description
Title
Kinetics and radiative processes of a xenon and iodine inductive RF discharge at low pressure
Author(s)
Barnes, Paul Nathan
Issue Date
1996
Department of Study
Physics
Discipline
Physics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Chemistry, Physical
Physics, Molecular
Physics, Atomic
Language
eng
Abstract
An investigation is conducted to determine the kinetics and radiative processes involved in a low pressure, $0.5-5$ torr, discharge sustained in Xe and I$\sb2.$ The discharge is excited with an RF inductive power source. The diagnostics applied in this study include laser-induced fluorescence (LIF), absorption spectroscopy, emission spectroscopy, microwave interferometry, and microwave absorption. Results from this research indicate that Xe + I$\sb2\sp{*}\sp{*}{\to}$ XeI* + I is the major precursor reaction leading to XeI* radiation. This conclusion differs from those resulting from research performed at higher pressures. Those studies concluded that the harpoon reaction or ionic recombination is the precursor process. In a time modulated inductively coupled discharge, the emission of I* decays on the order of hundreds of microseconds due to ion-ion neutralization consistent with the Landau-Zener theory of ion-ion neutralization. Decay of the electron density is also hundreds of microseconds for the same discharge. Electron-ion recombination leading to excited states is not an important source of emission in the discharge at high or low powers.
The similarity in the observed 512 nm and 804 nm emission indicates that the upper levels of atomic iodine are populated in the same proportions across the radius of the discharge. The difference between the I* emission at 206 nm and I** emission indicates that the upper levels of atomic iodine leading to I** emission are populated in a different proportion than the first excited states of atomic iodine. The emission of the D, E, and F states of I$\sb2$ behave similarly, indicating that the relative populations of these upper states are generally maintained across the plasma radius. The Xe**(6p$\sb{12})$ density results from electron excitation of the Xe* metastable state at higher powers. At lower powers, the population of the Xe**(6p$\sb{12})$ state is largely by direct electron impact with ground state xenon. The emissions from a capacitively coupled discharge at low powers are largely a result of direct electron excitation of species.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
