Electronic structures of endohedral N@C60, O@C60 and F@C60 (original) (raw)
Electronic structure of C60 semiconductors under controlled doping with B, N, and Co atoms
Diamond and Related Materials, 2008
We present our recent studies of ab initio density functional theory (DFT) calculations of the electronic structures of several selected n-and p-type doped C 60 semiconductors. A super-cell approach was used. We performed a series of ab initio density functional computations to systematically study the changes of the electronic structure of C 60 semiconductors doped with boron, nitrogen and cobalt atoms. We found that boron and cobalt doped, face-centered cubic (FCC) C 60 solids have the electronic structures of n-type semiconductors. Nitrogen doped FCC C 60 solid has an electronic structure similar to those of a p-type semiconductor, with shallow impurity energy levels near the top of the valence bands of the host material.
Density functional study of structural and electronic properties of Aln@C60
SOLID STATE PHYSICS: Proceedings of the 58th DAE Solid State Physics Symposium 2013, 2014
Low-lying equilibrium geometric structures of Al n N (n ϭ 1-12) clusters obtained by an all-electron linear combination of atomic orbital approach, within spinpolarized density functional theory, are reported. The binding energy, dissociation energy, and stability of these clusters are studied within the local spin density approximation (LSDA) and the three-parameter hybrid generalized gradient approximation (GGA) due to Becke-Lee-Yang-Parr (B3LYP). Ionization potentials, electron affinities, hardness, and static dipole polarizabilities are calculated for the ground-state structures within the GGA. It is observed that symmetric structures with the nitrogen atom occupying the internal position are lowest-energy geometries. Generalized gradient approximation extends bond lengths as compared with the LSDA lengths. The odd-even oscillations in the dissociation energy, the second differences in energy, the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps, the ionization potential, the electron affinity, and the hardness are more pronounced within the GGA. The stability analysis based on the energies clearly shows the Al 7 N cluster to be endowed with special stability.
Geometric and electronic structures of C60H60, C60F60, and C60H36
The Journal of Physical Chemistry, 1991
The user has requested enhancement of the downloaded file. J. Phys. Chem. 1991, 95, 5163-5168 5763 that the stable cluster ions ((NH3),,.(CH$N),IH+ and I(NH3),.(CH3CHO),)H+, n + m = 5, have completed solvation shell structures as expressed in structures I.
Synthesis, characterization and DFT calculations of new ethynyl-bridged C60 derivatives
Tetrahedron, 2010
YbPO 4 crystals were synthesized by solid-state reaction and characterized by X-ray diffraction, infrared and Raman spectroscopies. The electronic structure and optical properties of YbPO 4 such as the energy band structures, density of states and chemical bonds were calculated with the Density Functional Theory (DFT) for the first time. We present a combination of the GGA and the LDA + U approaches in order to obtain appropriate results due to the strong Coulomb repulsion between the highly localized 4f electrons of rare earth atoms. The linear photon-energy-dependent dielectric functions, conductivity and some optical constants such as refractive index, reflectivity and absorption coefficients were determined. The calculated total and partial densities of states indicate that the top of valance band is built upon O-2p states with P-3p states via r (P-O) interactions, and the conduction bands mostly originate from Yb-5d states.
Electronic structure of A4C60: Joint effect of electron correlation and vibronic interactions
Physical Review B, 1999
Effects of electron correlation, intrasite vibronic interaction, and merohedral disorder on the electronic structure of K4C60 are investigated with a model approach taking into account all essential interactions in the lowest unoccupied molecular orbital (LUMO) band. The self-energy was calculated within the GW approximation with self-consistency after the quasiparticle Green function starting from Hartree-Fock band structure. The insulating state arises due to interorbital charge disproportionation within the LUMO band while the band gap is strongly reduced by effects of long-range electron correlation. The results of the calculations are in reasonable agreement with experiment, providing evidence for a Jahn-Teller induced transition from a Mott-Hubbard to a band insulator state.
Electronic structure and bonding of C60 to metals
Synthetic Metals, 1993
The electron distribution and orbital interactions of C60 with metals coordinated at different sites on the outside of the fuUerene are evaluated with the Fenske-Hall molecular orbital method. The characters and nodal properties of the frontier orbitals of C60 are first evaluated in terms of basis transformations to the C2 units that join the pentagons and to the C5 units of the pentagons in the Cso molecule. The highest occupied molecular orbital (HOMO, hu symmetry) of C60 is largely ~r bonding between the carbon atom pairs that join adjacent pentagons. The lowest unoccupied molecular orbital (LUMO, tlu symmetry) is predominantly ~-antibonding between these carbon atom pairs. These orbital characters and energies are well situated for synergistic bonding of a metal atom to the carbon-caxbon pair between the pentagons, in which the HOMO of C60 donates a electron density to the metal, and the LUMO of C60 accepts ~r electron density from the metal. The electron donation and acceptance between the individual molecular orbitals of the C60 molecule and the orbitals of a metal at different possible bonding sites of C~o are probed with a Ag ÷ ion. It is found that the bonding is favored at the site between the pentagons and that many different orbitals of C~o are involved in the interaction. The net bonding of Ag ÷ to C60 is weaker than to ethylene. Calculations are also carried out on the organometallic complexes C60Pt(PHa)2 and (C2H4)Pt(PH3)2. The net bonding of ethylene and C80 to platinum is found to be very similar in these cases. A significant difference in this case is that the net negative charge on C60 is more delocalized in the carbon cluster in contrast to the localized charge on ethylene.
Physical Review B Condensed Matter and Materials Physics, 2010
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.
Structure and Energetics of (C60)22+Conformers: Quantum Chemical Studies
Bulletin of the Korean Chemical Society, 2010
The geometrical structures and energetics of positively doubly charged fullerene dimer (C60)2 2+ conformers were studied using semiempirical PM3 and MNDO, Hartree-Fock (HF), and Hybrid B3LYP density functional methods. The shape of the HOMO-LUMO for the three conformers was also analyzed. The gauche conformer was the most stable of the three conformers. The anti conformer was more stable than the syn conformer.