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Antonio G. Souza Filho

Publications and source records attributed to Antonio G. Souza Filho.

3 recordsLinked to original sources

Fostering cultural change in research through innovative knowledge sharing, evaluation, and community engagement strategies

Bringing together researchers, funders, industry partners, and publishers from 14 countries across 5 continents, we advance the debate around open-science, assessment and learning. We introduce an integrative "open knowledge system" framework linking knowledge production, validation, assessment, and reuse into one ecosystem view, and translate it into actionable recommendations for each stakeholder. Shifting focus to modular, machine-readable knowledge objects, these recommendations are intended to help diagnose misaligned incentives and guide reforms that properly value all scientific contributions.

cs.SI↗

A new class of organic molecular magnets

Using detailed first principles calculations, we have found a new class of stable organic molecular magnets based on zwitterionic molecules possessing donor, $π$ bridge, and acceptor groups. These molecules are organic molecules containing only C, H and N. The quantum mechanical nature of the magnetic properties originates from the conjugated $π$ bridge (involving only p electrons) where the exchange interactions between electron spin are relatively strong and local and are independent of the length of the $π$ bridge, enabling the easy construction of a molecular magnetic device with specified length.

cond-mat.mtrl-sci↗

Selection Rules for One- and Two-Photon Absorption by Excitons in Carbon Nanotubes

Recent optical absorption/emission experiments showed that the lower energy optical transitions in carbon nanotubes are excitonic in nature, as predicted by theory. These experiments were based on the symmetry aspects of free electron-hole states and bound excitonic states. The present work shows, however, that group theory does not predict the selection rules needed to explain the two photon experiments. We obtain the symmetries and selection rules for the optical transitions of excitons in single-wall carbon nanotubes within the approach of the group of the wavevector, thus providing important information for the interpretation of theoretical and experimental optical spectra of these materials.

cond-mat.mtrl-sci↗