An apparatus for studying momentum-resolved electron-impact dissociative and non-dissociative ionisation
Physical Research Laboratory, Ahmedabad 380009, India
Corresponding author: a firstname.lastname@example.org
Revised: 21 July 2005
Published online: 4 October 2005
A spectrometer for recoil ion momentum measurements has been built for studying electron impact ionisation and dissociation of molecules. The apparatus is described in detail, highlighting its capabilities, as well as differences in design from the ones already in use elsewhere. Momentum spectra of ions resulting from 1300 eV electron impact on CO2 are presented. We observe a broad momentum distribution for the dissociative ionisation reaction leading to the formation of C+, and two momentum groups in the CO+ and O+ channel. By recording multiple ions arising from the same dissociative ionisation event, we also demonstrate the formation of fragment pairs O+:CO+, C+:O+, and O+:O+.
PACS: 34.50.Gb – Electronic excitation and ionization of molecules; intermediate molecular states (including lifetimes, state mixing, etc.) / 34.80.Gs – Molecular excitation and ionization by electron impact / 39.90.+d – Other instrumentation and techniques for atomic and molecular physics
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005