The Role of Momentum Partitioning in Covariance Ion Imaging Analysis
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Engineering topics
McManus, Joseph W.
Publications and source records attributed to McManus, Joseph W..
Exploring the ultrafast and isomer-dependent photodissociation of iodothiophenes via site-selective ionization
The dissociation dynamics of UV pumped iodothiophene molecules are investigated using velocity map ion imaging, in combination with site-selective extreme ultraviolet ionization of the iodine atom.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Two-Dimensional Projected-Momentum Covariance Mapping for Coulomb Explosion Imaging
We introduce projected-momentum covariance mapping, an extension of recoil-frame covariance mapping for 2D ion imaging studies. By considering the two-dimensional projection of the ion momenta as recorded by the detector, one opens the door to a complex suite of analysis tools adapted from three-dimensional momentum imaging studies. This includes the use of different frames of reference to unravel the dynamics of fragmentation and the application of fragment momentum constraints to isolate specific fragmentation channels. The technique is demonstrated on data from a two-dimensional ion imaging study of the Coulomb explosion of the cis and trans isomers of 1,2-dichloroethene, following strong-field ionization by an intense near-infrared femtosecond laser pulse. Classical simulations are used to guide the interpretation of projected-momentum covariance maps. The results offer a detailed insight into the distinct Coulomb explosion dynamics for this pair of isomers and lay the groundwork for future time-resolved studies of photoisomerization dynamics in this molecular system.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Direct momentum imaging of charge transfer following site-selective ionization
We study ultrafast charge rearrangement in dissociating 2-iodopropane (2-C 3 H 7 I) using site-selective core-ionization at the iodine atom. Clear signatures of electron transfer between the neutral propyl fragment and multiply charged iodine ions are observed in the recorded delay-dependent ion momentum distributions. The detected charge transfer pathway is only favorable within a small (few angstrom), charge-state-dependent spatial window located at C-I distances longer than that of the neutral ground-state molecule. Lastly, these results offer new insights into the physics underpinning charge transfer in isolated molecules and pave the way for a new class of time-resolved studies.
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Disentangling sequential and concerted fragmentations of molecular polycations with covariant native frame analysis
Using covariance analysis methods, we study the fragmentation dynamics of multiply ionized 1- and 2-iodopropane. Signatures of isomer-specific nuclear motion occurring during sequential fragmentation pathways are identified.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗