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## Full-Text Articles in Physics

Non-Dipolar Electron Angular Distributions From Fixed-In-Space Molecules, Renaud Guillemin, Oliver Hemmers, Dennis W. Lindle, E. Shigemasa, K. Le Guen, D. Ceolin, C. Miron, N. Leclercq, P. Morin, Marc Simon, P. W. Langhoff

#### Non-Dipolar Electron Angular Distributions From Fixed-In-Space Molecules, Renaud Guillemin, Oliver Hemmers, Dennis W. Lindle, E. Shigemasa, K. Le Guen, D. Ceolin, C. Miron, N. Leclercq, P. Morin, Marc Simon, P. W. Langhoff

*Environmental Studies Faculty Publications*

The first indication of nondipole effects in the azimuthal dependence of photoelectron angular distributions emitted from fixed-in-space molecules is demonstrated in N_{2}. Comparison of the results with angular distributions observed for randomly oriented molecules and theoretical derivations for the nondipole correction first order in photon momentum suggests that higher orders will be needed to describe distributions measured in the molecular frame.

Exploring The Limits Of The Dipole Approximation With Angle-Resolved Electron Time-Of-Flight Spectrometry, Sierra Laidman, Monica Pangilinan, Renaud Guillemin, Sung Woo Yu, Gunnar Ohrwall, Dennis W. Lindle, Oliver Hemmers

#### Exploring The Limits Of The Dipole Approximation With Angle-Resolved Electron Time-Of-Flight Spectrometry, Sierra Laidman, Monica Pangilinan, Renaud Guillemin, Sung Woo Yu, Gunnar Ohrwall, Dennis W. Lindle, Oliver Hemmers

*Environmental Studies Faculty Publications*

Understanding the electronic structure of atoms and molecules is fundamental in determining their basic properties as well as the interactions that occur with different particles such as light. One such interaction is single photoionization; a process in which a photon collides with an atom or molecule and an electron with a certain kinetic energy is emitted, leaving behind a residual ion. Theoretical models of electronic structures use the dipole approximation to simplify x-ray interactions by assuming that the electromagnetic field of the radiation, expressed as a Taylor-series expansion, can be simplified by using only the first term. It has been ...

Antiprotons And Other Nuclear Matters , Brett Steven Fadem

#### Antiprotons And Other Nuclear Matters , Brett Steven Fadem

*Retrospective Theses and Dissertations*

We present antiproton invariant multiplicities from Experiment 941 using 12 and 19 GeV/c proton beams incident upon targets of Pb, Cu and Be. Since we are currently unable to calculate antiproton yields in this regime from first principles, we must rely on empirical data in order to answer questions involving antibaryon production at these energies. Typically, the motivation for studying this topic using proton-nucleus (p-A) collisions is to shed light on antiproton production in the more complicated collisions between heavy nuclei (A-A). For this reason, this thesis will use the measured target dependence to illuminate issues relating to annihilation ...