[en] 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

No abstract available

[en] Clusters of 2 x 10³ to 4 x 10⁴ Ar atoms are Coulomb exploded in intense (up to 8 x 10¹⁵ W cm^-2 ) laser fields. The dependence of multiply charged argon ion energies on the polarization state of light is probed. A directional asymmetry in the ion-explosion energies is observed for the highest charge states. The ion-energy distribution consists of a low-energy isotropic component, and a high-energy anisotropic one. The results are discussed in terms of an asymmetric Coulomb-explosion scenario

No abstract available

[en] Resonant scattering of low energy electrons from naphthalene has been investigated using electron transmission spectroscopy. The transmission spectrum of naphthalene yields a value of -0.20+-0.05 eV for the first electron affinity. The first and second excited states of C₁₀H₈^- are detected at 0.96+-0.1 eV and 1.55+-0.13 eV. Resonant structure is also observed at 5.29+-0.1 eV and 7.55+-0.05 eV; it is suggested that the former resonance is the previously unidentified peak in the threshold electron excitation spectrum of Compton and co-workers. (Auth.)

[en] Ghosh and Ghosh (1982) have recently suggested the use of a simple equation to calculate the rate constants for ion-molecule reactions. This study points out inadequacies in the suggested approach and draws attention to experimental rate constants which are orders of magnitude different from the values deduced from the proposed equation. (author)

[en] In the contemporary scenario, atomic, molecular and optical (AMO) science focuses on the physical and chemical properties of the common building blocks of matter - atoms, molecules and light. The main characteristic of AMO science is that it is both an intellectually stimulating fundamental science and a powerful enabling science that supports an increasing number of other important areas of science and technology. In brief, the fundamental interests in atoms, molecules and clusters (as well as their ions) include studies of their structure and properties, their optical interactions, collisional properties, including quantum state-resolved studies, and interactions with external fields, solids and surfaces. Fundamental aspects of present-day optical sciences include studies of laser spectroscopy, nonlinear optics, quantum optics, optical interactions with condensed matter, ultrafast optics and coherent light sources. The enabling aspect of AMO science derives from efforts to control atoms, molecules, clusters, charged particles and light more precisely, to accurately to determine, experimentally and theoretically, their properties, and to invent new, methods of generating light with tailor-made properties

[en] An overview is provided of the utility of a new ion collision technique, translational energy spectrometry (TES), in probing molecular potential energy surfaces. TES is a gas-phase collisional technique in which the analysis of the changes in the kinetic energy of a projectile ion which has undergone collision with a neutral atom/molecule furnishes information about the interaction potential between the projectile and the target. An advantage this technique offers over conventional spectroscopic and laser-based methods is relatively easy access to intrinsically unstable species such as singly charged radicals and multiply charged molecular ions. (author). 13 refs., 5 figs

[en] The apparent stability of many doubly and triply charged molecular ions can be rationalised by a curve crossing model in which predominantly repulsive potential energy functions are perturbed by charge polarisation states to yield potential wells. Experimental techniques for locating these potential minima are discussed. Results of an emerging new class of collisions experiments - those involving multiply charged molecular projectiles - are presented. 51 refs

[en] A new technique is described which enables measurements to be made of the lifetime of metastable states of molecular ions. Translational energy spectrometry is utilised to study the dissociation of doubly charged molecules; the resulting fragment-ion kinetic-energy spectra yield information on the lifetimes of specific quantal states in the range from nanoseconds to fractions of a millisecond. (orig.)