Date of Award

5-2003

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Engineering Physics

First Advisor

Paul J. Wolf, PhD

Abstract

The objective of this research is to study the effects of noble gases on atomic strontium and diatomic bismuth visible transitions, Specifically, this research seeks to determine if the line broadening and, in the case of atomic strontium, line shifting rates of these transitions in the presence of noble gases depend on the total angular momenta of the energy states involved. It has been known for more than a century that atomic and molecular spectral lines are broadened and shifted by perturbing species. While a considerable body of theoretical work has been accomplished on this topic over the years, only recently have experimental techniques been developed to precisely measure these effects. In particular, the advent of the narrowband tunable dye laser has advanced the state of the art and made high-resolution measurements of spectral line profiles possible. With such data, it is now possible to precisely quantify the broadening and shifting of spectral lines by perturbing species. Spectral line broadening and shifting rates of the atomic strontium transitions perturbed by helium, neon, argon, krypton, and xenon were measured using tunable laser absorption spectroscopy. Noble gas pressures ranged from 0 to 1000 Torr Broadening and shifting rates were converted to cross section and used to determine the Lennard-Jones (6-12) difference potential constants according to the theory of line perturbations by elastic collisions. Spectral line broadening rates of the diatomic bismuth were measured using laser-induced fluorescence spectroscopy.

AFIT Designator

AFIT-DSP-ENP-03-01

DTIC Accession Number

ADA415592

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