Recent Advances in Ion Imaging Measurements of Electron-Molecule Interactions*

Ion fragment momentum imaging experiments employing reaction microscopes [1,2] or velocity-slice imaging spectrometers [3], enable the highly differential momentum imaging of multiple fragment ions over large collection angles up to 4π steradians. These capabilities allow precise measurements of electron molecule interactions resulting in dissociation through the analysis of fragment ion kinetic energy and angular distributions. This information is particularly valuable for comparison with, or testing of, electronic structure calculations to predict the resonance energy and the kinetic energy released in dissociation, and electron scattering theory to predict the attachment or scattering probability in the body-fixed frame of the molecule.

In this tutorial I will describe some of the recent advances in anion and cation fragment imaging, including the current limitations and challenges for experiments employing these methods. We will discuss different momentum imaging spectrometers, detector technologies, and analysis software, and how each can be applied in experiments to investigate dynamics in electron-molecule collisions. 

References

[1]           D S Slaughter, A Belkacem, C W McCurdy, T N Rescigno and D J Haxton, J. Phys. B, 49, (2016), 222001. https://doi.org/10.1088/0953-4075/49/22/222001

[2]           Ren, X., Wang, E., Skitnevskaya, A.D. et al. Nature Phys., 14, (2018), 1062–1066. https://doi.org/10.1038/s41567-018-0214-9

[3]           E Krishnakumar, V S Prabhudesai and N J Mason, Nature Phys., 14, (2018), 149-153. https://doi.org/10.1038/nphys4289