Research Fellows Directory
Dr Kate Nixon
University of Manchester
Electron collisions at low energies play a fundamental role in a wide range of important areas. These include: studying the Earth’s upper atmosphere leading to climate change, the development of new lasers and novel forms of lighting, and the treatment of cancers with radiotherapies. To understand the role of low energy electron collisions in these applications, and to predict their effect over wide range of varied situations, it is essential to develop comprehensive quantum mechanical models of the collision, and to evaluate their accuracy by comparison with precise experimental data. Electron impact ionisation experiments like those undertaken in this research, provides the most detailed data against which theoretical predictions can be compared. These new data are integral in the evaluation and development of new models, which then allow an understanding of these important processes to be developed.
Recently measured data for ionization of helium and CH4 have tested the models in detail. These reveal that the collisions with simple atoms are well understood, with excellent agreement being found between experiment and theory. By contrast, electron-molecule ionisation models are new and require considerably more development to obtain reliable predictions.
A new apparatus to measure the first data of ionisation from aligned atoms and molecules is being developed. In these experiments a high power laser is used to control the orientation of the target to give entirely new data. Collaborations with theoretical colleagues in the USA and Australia who are currently developing the most sophisticated models of these processes are also underway. These models will then be used to make predictions of the effect of these ionising collisions in the important areas described above.