Unique Bonding Nature of Carbon-Substituted Be2 Dimer inside the Carbon (sp2) Network
Résumé
Controlled doping of active carbon materials (viz., graphenes, carbonnanotubes etc.) may lead to the enhancement of their desired properties. The leaststudied case of C/Be substitution offers an attractive possibility in this respect. Theinteractions of Be2 with Be or C atoms are dominated by the large repulsive Pauliexchange contributions, which in turn offsets the attractive interactions leading torelatively small binding energies. The Be2 dimer, e.g., after being doped inside a planarcarbon network, undergoes orbital adjustments due to charge transfer and unusualintermolecular interactions and is oriented perpendicular to the plane of the carbonnetwork with the Be−Be bond center located inside the plane. The present theoreticalinvestigation on the nature of bonding in C/Be2 exchange complexes, using state of theart quantum chemical techniques, reveals a sp2 carbon-like bonding scheme in Be2 arising due to the molecular hybridization of σand two π orbitals. The perturbations imposed by doped Be2 dimers exhibit a local character of the structural and electronicproperties of the complexes, and the separation by two carbon atoms between beryllium active centers is sufficient to considerthese centers as independent sites.
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