UBC Theses and Dissertations
Binary (e,2e) spectroscopy and momentum space chemistry Cook, John P.D.
Binary (e,2e) spectroscopy is an intermediate energy electron scattering coincidence technique measuring the binding energy and spherically-averaged momentum distributions of individual valence electrons in small gaseous molecules. Momentum space chemistry is a term used to refer to the study of the attributes of molecular orbitals in the momentum space representation, rather than the usual position space representation. The relation between the two spaces is the Fourier Transform. This thesis discusses experimental measurements and theoretical calculation of the binding energy spectra and/or momentum distributions of. H₂S, COS, C0₂, NO and 0₂ in detail. It also attempts to bring into the ken of ordinary chemistry concepts and principles for dealing with momentum-space molecular orbital density functions, which are essential to the understanding of the nature of momentum distributions. In order to illustrate this, specific examples of theoretical momentum and charge density maps for several molecules are discussed. Significant new understanding of the electronic structure of these molecules is attained. The design, construction, and preliminary testing of a new binary (e,2e) spectrometer incorporating a multi-channel plate detector for improved data collection efficiency is presented. Finally, some propositions for future directions of study are put forward.
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