1 research outputs found

    Structure, electronic, and optical properties of TiO 2 atomic clusters: An ab initio study

    Get PDF
    Atomic clusters of TiO 2 are modeled by means of state-of-the-art techniques to characterize their structural, electronic and optical properties. We combine ab initio molecular dynamics, static density functional theory, time-dependent density functional theory, and many body techniques, to provide a deep and comprehensive characterization of these systems. TiO 2 clusters can be considered as the starting seeds for the synthesis of larger nanostructures, which are of technological interest in photocatalysis and photovoltaics. In this work, we prove that clusters with anatase symmetry are energetically stable and can be considered as the starting seeds to growth much larger and complex nanostructures. The electronic gap of these inorganic molecules is investigated, and shown to be larger than the optical gap by almost 4 eV. Therefore, strong excitonic effects appear in these systems, much more than in the corresponding bulk phase. Moreover, the use of various levels of theory demonstrates that charge transfer effects play an important role under photon absorption, and therefore the use of adiabatic functionals in time dependent density functional theory has to be carefully evaluated. © 2011 American Institute of Physics.We acknowledge financial support from Spanish MEC (FIS2011-65702-C02-01), ACI-Promociona (ACI2009- 1036), Grupos Consolidados UPV/EHU del Gobierno Vasco (IT-319-07), the European Research Council Advanced Grant DYNamo (ERC-2010-AdG -Proposal No. 267374) and the European Research Council Starting Grant DEDOM (Grant Agreement No. 207441). We acknowledge support by the Barcelona Supercomputing Center, “Red Espanola de Supercomputacion,” SGIker ARINA (UPV/EHU), Transna tional Access Programme HPC-Europe++, CNS-Ipicyt, Mexico and CINECA. L.C. acknowledges funding from UPV/EHU through the “Ayudas de Especialización para Investigadores Doctores” program. A.H.R. has been supported by CONACyT Mexico under projects J-152153-F, and TAMU-CONACyT.Peer Reviewe
    corecore