Electronic structure and localization properties ofC60Tanclusters(n=1

Abstract

The electronic structure and the electronic localization properties of the exohedrally doped fullerene C 60 Ta, C 60 Ta 2 , and C 60 Ta 3 systems are studied in the framework of density functional theory calculations. The effect of doping the fullerene network with Ta impurities results in modifications of the Kohn-Sham energy levels spectrum in the highest occupied molecular orbital-lowest unoccupied molecular orbital ͑HOMO-LUMO͒ region and a drastic HOMO-LUMO band-gap reduction. In the vicinity of the HOMO, most of the occupied electronic states are Ta-like for C 60 Ta and C 60 Ta 2 , while C-like states or mixed C-Ta-like states are predominant for the case of C 60 Ta 3 . In all cases, we observe a conspicuous charge transfer from the Ta to the neighboring C atoms, Mulliken charges are positive on the Ta atoms and equal to 2.12 ͑C 60 Ta͒, 1.77/1.80 ͑C 60 Ta 2 ͒, and 1.61/1.62 ͑C 60 Ta 3 ͒. The values of the valence charges on the Ta atoms reflect their coordination environment and are the largest in C 60 Ta 3 ͑3.00/3.25͒. This is compatible with the existence of three nearest neighbors ͑two Ta and one C͒ for each one of the Ta atoms in C 60 Ta 3 . We provide an insight into the physical nature of bonding by means of an accurate electronic structure analysis in terms of the electron localization function and the maximally localized Wannier orbitals. Among the Ta valence electrons, the most localized ones are those not involved in bond formation, charge transfer effects concurring to the establishment of ionic-covalent bonds between the Ta and the neighboring C atoms.

Exohedral M–C60 and M2–C60 (M = Pt, Pd) systems as tunable-gap building blocks for nanoarchitecture and nanocatalysis

“…Previous models of fullerene-metal complexes 39,40 were used to construct the initial structures for the present study. The reliability of these models was extensively benchmarked towards experiments and former calculations.…”

Synthesis and structure of ruthenium-fullerides

“…25 It is worth mentioning that most of these structural studies have used a single characterization techniques such as Raman spectroscopy, 19 XPS, 15 or TEM. 21 Some theoretical works, using Density Functional Theory (DFT), on exohedral fullerenes have been mainly devoted to the interaction between C 60 and alkali atoms: Na, K, [26][27][28][29] and in a lesser extent TM, mainly V, 30 Ni, 31 Au 32,33 and Ta 34,35 and more recently with Pd and Pt atoms. 36 To our knowledge, no theoretical studies on the existence or the possible structures of -C 60 -TM-C 60linear chains have been reported.…”