Electron-induced dissociation dynamics studied using covariance-map imaging

Abstract

Recently, covariance analysis has found significant use in the field of chemical reaction dynamics. When coupled with data from product time-of-flight mass spectrometry and/or or multi-mass velocity-map imaging, it allows...

Spiers Memorial Lecture: New directions in molecular scattering

“…Recently, this process has been studied using ion imaging in a crossed-beams geometry. [280][281][282][283][284][285] The use of pixel imaging mass spectrometry and covariance imaging allows identication of fragments arising from the same parent ions and detection of doubly charged ions on a large background of singly charged ions. 281 This is particularly useful when analyzing the fragmentation patterns of larger polyatomic molecules and provides accurate observations of the decomposition channels that occur in the violent ionization event.…”

Imaging the Dynamics of the Electron Ionization of C2F6

“…Recently we have begun to explore the dissociation dynamics of multiply charged ions ,− by using multimass velocity-map ion imaging (VMI) to record scattering distributions for all ionic products of electron ionization (EI) within a single measurement. , The predominant outcome from an electron–molecule collision that leads to ionization is the formation of a singly charged parent ion. However, some proportion of collisions will create multiply charged ions via either an Auger cascade or a secondary collision of one of the departing electrons with another bound electron. , …”

“…Any ion signal arising from fragmentation of a dication into two or more singly charged daughter ions invariably overlaps with signals arising from the dominant singly charged channels. Our approach to resolving the dynamics of multiply charged ions is to employ covariance analysis, − ,, a statistical method that reveals correlations between fragments even in the presence of much larger signals from uncorrelated events. The correlations of greatest interest to us are between product ion time-of-flight (TOF) spectra and product pair recoil velocities.…”

“…Recently we have begun to explore the dissociation dynamics of multiply charged ions 35 , 39 − 42 by using multimass velocity-map ion imaging (VMI) to record scattering distributions for all ionic products of electron ionization (EI) within a single measurement. 40 , 41 The predominant outcome from an electron–molecule collision that leads to ionization is the formation of a singly charged parent ion.…”