Nanomaterials and Nanochemistry

Nanomaterials are a fast developing field of research and applications lie in many separate domains, such as in hi-tech (optics, electronics, biology, aeronautics), but also in consumer industries (automotive, concrete, surface treatments (including paints), cosmetics, etc.)

Dans le sillage de la physico-chimie sous rayonnements : vers l’institut des sciences moléculaires d’Orsay

Cet article évoque le cheminement qui a conduit une partie de la communauté scientifique d’Orsay, dès 1960, de la chimie sous rayonnements à la physique des collisions atomiques et moléculaires et à la photophysique, pour aboutir à la création, en 2010, de l’institut des sciences moléculaires d’Orsay, aujourd’hui organisé selon trois grands pôles : la physique moléculaire, les nanosciences, la physique pour la biologie. Si la personnalité des pionniers a joué un rôle essentiel dans l’établissement des concepts, les avancées techniques et les découvertes fortuites ont eu leur importance.This article evokes the pathway which, since 1960, has led a part of the scientific community at Orsay, from radiation chemistry to atomic and molecular collision physics and photophysics, resulting, by intensifying exchanges, in the creation of the Institute for Molecular Sciences at Orsay, presently organized along three main centers of expertise: molecular physics, nanosciences, physics for biology. If the pioneers’ personal qualities have played a major role in the establishment of concepts, technical advances and fortuitous discoveries have made important contributions

Chemically induced morphology change in cluster-based nanostructures

Preformed clusters carrying surfactant are used as primary blocks for the building of nanostructures. Self-assembly of silver atom based clusters, soft landed on a HOPG surface, generates a large variety of new architectures depending on the nature and on the concentration on the impurities. Fractal shapes fragmentated into multiple compact islands, and chainlike structures might be formed. A strong local enhancement of the silver atom mobility at the surface of islands is responsible for those morphology changes.status: publishe

Electronic effects in the dissociative ionisation of pyrene clusters

International audienceWe present a combined experimental and theoretical study on the dissociative ionisation of clusters of pyrene. We measured the experimental appearance energies in the photon energy range 7.2–12.0 eV of the fragments formed from neutral monomer loss for clusters up to the hexamer. The results obtained show a deviation from statistical dissociation. From electronic structure calculations, we suggest that the role of excited states must be considered in the interpretation of experimental results, even in these relatively large systems. Non-statistical effects in the dissociative ionization process of polycyclic aromatic hydrocarbon (PAH) clusters may have an impact on the assessment of mechanisms determining the stability of these clusters in astrophysical environments

Effects of hydrogen dissociation on the infrared emission spectra of naphthalene: theoretical modeling

International audienceThe IR emission spectroscopy of naphthalene and its singly- and doubly-dehydrogenated radicals has been modeled using kinetic Monte Carlo simulations, taking into account the various relaxation pathways of radiative emission and hydrogen loss. Our modeling relies on quantum chemistry ingredients that were obtained from dedicated calculations based on density functional theory, including explicitly anharmonicity contributions. Our results show that the fragmentation products significantly contribute to the overall IR emission spectrum, especially to the intensity ratios between bands. Owing to the likely presence of polycyclic aromatic hydrocarbons in the interstellar medium, these findings are particularly relevant in the astrophysical context

Development and Validation of a Cytogenetic Prognostic Index Predicting Survival in Multiple Myeloma

International audienc