Date of Award

6-1996

Degree Name

Doctor of Philosophy

Department

Physics

First Advisor

Dr. John A. Tanis

Second Advisor

Dr. Norah Berrah

Third Advisor

Dr. Dean W. Halderson

Fourth Advisor

Dr. Emanuel Y . Kamber

Abstract

Projectile charge changing and target ionization cross sections are measured for 0.5 to 8 qMeV Li^q+ + He (q=1,2,3) collisions. Total cross sections for single-electron capture (for L i^1,2,3+) and single-electron loss (for L i^1,2+) are obtained and compared to existing experimental and theoretical data. Also, single and double target ionization of He associated with specific outgoing projectile charge states are identified using coincidence techniques. Cross sections for target ionization associated with no projectile charge change (direct ionization), single-electron capture, and single-electron loss are measured and compared to existing experimental data and to available calculations. Double-to-single target ionization ratios R are obtained and interpreted in terms of theoretical formulations involving electron - nucleus interactions and electron - electron interactions. It is found that R for direct ionization is nearly independent of the incident projectile charge state and can be described by the semi-empirical scaling rule of Knudsen et al. (1984). However, the R values associated with single-electron loss and single electron capture by the projectile depend strongly on the incident charge state of the projectile. Furthermore, R for a given incoming projectile charge state varies strongly with the reaction channel. Effective charges for Li^+ and Li2^+ associated with single and double target ionization are also calculated.

In the second part of this dissertation the control program and data acquisition software for an electron spectrometer system utilizing two plane-mirror analyzers (PMA) are described. This system will be used to measure the energy and angle of electrons ejected in ion-atom collisions.

Comments

Fifth Advisor: Dr. Frank L. Severance

Access Setting

Dissertation-Open Access

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