Monocentric close-coupling expansion to provide ejected electron distributions for ionization In atomic collisions

Area of Science:

• Atomic and Molecular Physics
• Quantum Mechanics
• Computational Physics

Background:

• Positron-atom collisions are fundamental in understanding matter-antimatter interactions.
• Accurate theoretical methods are crucial for interpreting experimental results in atomic collisions.

Purpose of the Study:

• To introduce and apply a novel monocentric close-coupling expansion method.
• To calculate total ionization cross sections for positron-hydrogen collisions.
• To obtain reliable ejected electron distributions, extending beyond standard close-coupling capabilities.

Main Methods:

• A new monocentric close-coupling expansion was developed.
• The expansion utilizes spherical Bessel functions confined within a finite box.
• The method was implemented for positron-hydrogen (e+H(1s)) collisions.

Main Results:

• The method successfully calculated total ionization cross sections.
• Reliable ejected electron distributions were obtained.
• The results align with and support recent classical descriptions of these collisions.

Conclusions:

• The presented close-coupling expansion is a viable and effective method for studying positron-atom collisions.
• This approach provides valuable insights into ejected electron dynamics, a key aspect of ionization processes.
• The findings validate and extend previous theoretical models in the field.