A density-functional theory investigation of the electronic structure of the active carbon graphite-like and amorphous domains

Spin Filter Circuit Design Based on a Finite Single-Walled Carbon Nanotube of the Zigzag Type

“…One observes from Figure for the 2-MP–TA–(10,0)SWCNT–TA–2-MP system that the spin density is preferentially localized on the edge atoms of the zSWCNT, in accordance with previous PW-DFT results. − We ascribe this phenomenon to the stabilizing effect of the H atoms that partially saturate the edges. The change of the overall spin of the system does not seem to affect the spin density localization, suggesting that the system is half-metallic. , In this context, we point out that half-metallicity has been established previously for pure zSWCNTs, which possess an AFM ground state, as well as for zSWCNTs doped by B atoms . Covalently grafting substituents that can participate in π-conjugation with the aromatic system of the zSWCNT thus preserves the partial magnetic moment observed previously for the nonmodified zSWCNT (Figure a).…”

“…The change of the overall spin of the system does not seem to affect the spin density localization, suggesting that the system is half-metallic. 24,25 In this context, we point out that half-metallicity has been established previously for pure zSWCNTs, which possess an AFM ground state, as well as for zSWCNTs doped by B atoms. 26 Covalently grafting substituents that can participate in π-conjugation with the aromatic system of the zSWCNT thus preserves the partial magnetic moment observed previously for the nonmodified zSWCNT (Figure 3a).…”

Theoretical Investigation of Anion-Radical States of Edge-Oxidized Carbon Model Clusters

“…1,11−13 This process results in a relatively acidic H + ion, while the electron is delocalized over the carbon moiety. Since both graphite-like and amorphous carbon particles are conjugated systems with a high degree of electron delocalization in the π-system, 14,15 addition of an electron to the aromatic system of carbon, that is, formation of a bulk anion-radical, might affect the properties of the whole particle.…”

“…Usually, carbon clusters in quantum-chemical studies are considered as neutral species. , However, a theoretical investigation of the ODH reaction over quinone groups grafted on the edge of graphene-derived carbon clusters indicated that upon addition of an H · radical to a quinone group the charge and spin of the attached species separate. ,− This process results in a relatively acidic H + ion, while the electron is delocalized over the carbon moiety. Since both graphite-like and amorphous carbon particles are conjugated systems with a high degree of electron delocalization in the π-system, , addition of an electron to the aromatic system of carbon, that is, formation of a bulk anion-radical, might affect the properties of the whole particle.…”

“…Therefore, we investigated the properties of a series of flat graphite-like carbon clusters and US-CNTs in different anion-radical states with density functional theory (DFT) and complete active space self-consistent field (CASSCF) methods to determine their relative stability and mark a difference in comparison with the neutral state. Since it has been recently shown that such systems might possess half-metallic properties with several multiplicity states of equal energy, , the dependency of the relative energy of the carbon clusters on its spin multiplicity state in each charge state was studied, paying attention to differences in the edge termination. − …”