A Primer on Electron-Atom Collisions

(adapted from C.C. Lin's 1996 Will Allis Prize Talk)

I) Introduction

• Opening remarks

II) Electron-Impact Excitation out of the ground state of Atoms

1. General
   • Optical method
   • Experimental Arrangement
2. Excitation of Helium
   • Excitation of singlet levels
   • Excitation of triplet levels
3. Excitation of Neon, Argon
   • Neon 2p⁵ns levels
   • Neon 2p⁵np levels
   • Argon 3p⁵4p levels and Neon 2p⁵3p levels
   • Neon 2p⁵4d levels
4. Pressure Effects
   • Low & High Pressure Cross sections
   • Radiation Trapping
   • Collision Transfer
     • Collision Transfer Mechanism for He 3³D
     • Mixed F collision transfer

III) Excitation out of Metastable Levels of Atoms

1. Motivation
   • Sources of metastable atoms
   • hollow cathode source
   • explaination of charge exchange
   • fast beam experiment
2. Helium
   • sample results: 3³S, 3³D
   • comparison to excitation from the ground state
   • comparison singlet-to-triplet
3. Argon
   • Argon energy level diagram
   • Plot of data

IV) Laser-Cooled Trapped Atoms for electron scattering Cross Sections

1. Introduction
   • principles
   • description of MOT experiment
2. Measurement of Total Scattering cross sections
   • Method to determine the total cross section
   • Results: Q^total(E)
3. Measurement of Ionization cross sections
   • Finding an upper bound on ionization
   • Effect of including small angle scattering
   • Results: Q^ion(E)