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Atomic collision theory

Collisions between particles on the atomic scale go on all around us, and are governed by the Laws of Quantum Mechanics. All light that we see is either due to or is influenced by such collisions. All chemical reactions are examples of molecular collisions. Accordingly, a quantitative understanding of the various collision processes has many scientific and industrial applications. For example, electron collisions with atoms are of importance in the fields of astrophysics, fusion energy, laser physics, plasma displays and the lighting industry.

Calculating atomic collisions is difficult because atoms have a countably infinite discrete spectrum and an uncountably infinite continuum. Additionally, the interactions are governed by the long-ranged Coulomb potential leading to formal mathematical problems in the description of the collisions.

Members of the Curtin group are responsible for the development of the Convergent Close-Coupling (CCC) method for calculating electron scattering on atoms. This approach is valid at all scattering energies, and has unified the approach to discrete excitation and ionising collisions. The method has been extended to positron scattering, with the explicit inclusion of positronium formation channels. More recently CCC has been extended to heavy projectiles such as protons and antiprotons, and electron/positron scattering on molecules.

Current projects include:

  • Development of formal collision theory for long-ranged potentials.
  • Computer code development for electron scattering on noble gases.
  • Implementation of the relativistic collision theory to electron scattering on heavy or highly ionised targets.
  • Calculation of fully differential electron-impact ionisation processes.
  • Development of the molecular CCC method for electron and positron collisions with diatomic molecules for fusion and astrophysical applications.
  • Development of CCC for proton or antiproton collisions with H or He atoms.