Structure and dynamics of molecules in high charge states

Abstract

The last decade has seen very substantial progress in the understanding of the formation and decay dynamics of multiply charged molecules, their structure, and their interactions with electrons, photons, atoms and molecules. Much of the growth that the subject has witnessed has been fuelled by developments in, and successful application of, techniques and methodologies that have enabled new classes of experiments to be performed. Examples of progress in techniques include the availability of storage ring technology for measurements of dication lifetimes and the interaction of dications with electrons, heavy ion accelerators and synchrotron radiation sources for studies that probe the dynamics of multielectron ejection from molecules, new types of detectors for measurement of multicoincidence spectra, and of novel ion sources, like electrospray, for production of very highly charged molecules, particularly biomolecules that normally exist only in the liquid phase. Examples of progress in methodologies include the development of ion translational energy spectrometry to make lifetime measurements, the application of covariance mapping and other multi-coincidence methods that make possible studies of the decay dynamics of highly charged molecules, and new applications of time-of-flight and ion beams apparatus to probe reactivities of highly charged molecules. Perhaps the most dramatic progress has been in studies that probe negatively charged molecules possessing more than a single charge. Substantial experimental work has been accomplished in the last few years on the formation of molecular dianions, and their decay by electron and photon impact. This Report provides a description of recent progress achieved in the above-mentioned facets of the structure and dynamics of molecules in high charge states, along with illustrative examples of the physics that has begun to be accessed.