Doctoral Dissertations

Keywords and Phrases

Ion-Atom Scattering; Kinematically Complete Experiment; Phase Shift; Projectile Coherence Properties; Single-Center Interference; Two-Center Interference

Abstract

"In recent years, the key role of the projectile coherence properties has been studied in several ion-atom scattering processes. These studies strongly suggested that cross sections could be significantly affected by the projectile coherence properties, especially for fast, heavy ions. In the present study, we used such coherence effects as a tool to sensitively analyze the few- body dynamics of the scattering process. To this end, we performed three kinematically complete experiments on fragmentation of H2 by 75 keV proton impacts. A novel approach was used to analyze coherence and interference effects in the observed cross-sections. The idea was to measure cross sections for coherent and incoherent projectiles simultaneously under otherwise identical experimental conditions. In the first experiment, single electron capture accompanied by vibrational dissociation was studied. Fully differential cross-sections (FDCS) were extracted for a fixed kinetic energy release and for two different fixed molecular orientations as a function of scattering angle. The coherent to incoherent FDCS ratios, which represents the interference term, revealed two distinct types of interference, single- and two-center interference. In the latter, an unexpected phase shift of π was found in the pronounced oscillations observed in the interference term. In the other two experiments, single capture accompanied by excitation of the second electron to a repulsive state, and Coulomb explosion due to double capture were studied. No clear signatures of single-center interference were observed for either process. Two-center interference was identified for dissociative transfer excitation. No π phase shift was observed for this process. Only a very weak two-center interference structure at most was found for double capture"--Abstract, page iv.

Advisor(s)

Schulz, Michael, 1959-

Committee Member(s)

Madison, Don H.
Hor, Yew San
Fischer, Daniel
Lee, Hyoung-Koo

Department(s)

Physics

Degree Name

Ph. D. in Physics

Sponsor(s)

National Science Foundation (U.S.)

Comments

National Science Foundation under Grants No. PHY-1401586 and No. PHY-1703109

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2018

Journal article titles appearing in thesis/dissertation

  • Fully differential study of capture with vibrational dissociation in P + H₂ collisions
  • Fully differential study of dissociative single capture and Coulomb explosion through double capture in P + H₂ collisions

Pagination

ix, 73 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2018 Basu Ram Lamichhane, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11291

Electronic OCLC #

1041858501

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Included in

Physics Commons

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