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Abstract: The electronic transport properties of the molecular device based on double‐cage fluorinated fullerene C20F18(NH)2C20F18 were studied theoretically. The results show that the device exhibits two negative differential resistance (NDR) peaks in its I‐V curve. The NDR peak under low bias voltage originates from the bias‐induced alignment of the molecular orbitals, and the conduction channel being suppressed at a certain bias voltage is the main reason for the NDR peak under a relatively high bias voltage. [ABSTRACT FROM AUTHOR]

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ABSTRACT: Stability and electronic property calculations are performed systematically based on density functional theory at the B3LYP/6-31G(d) level for Td C28 fullerene and exohedral fluorine and trifluoromethyl derivatives C28F4–n(CF3)n (n = 0,1,2,3,4). All the exohedral derivatives that are on the potential energy surfaces are kinetically stable with large HOMO-LUMO gaps. Further investigations show that binding energies of C28F4–n(CF3)n (n = 0,1,2,3,4) molecules are positive, suggesting they are thermodynamically stable. An analysis of the π-orbital axis vector indicates the high strain in Td C28 cage could be greatly released by fluorine and trifluoromethyl decorations. Mulliken charge analysis reveals that adding different electron groups to the Td C28 cage can cause remarkably different charge populations. In addition, from the ionization potential and electron affinity investigations, the C28F4–n(CF3)n (n = 0,1,2,3,4) molecules manifest weak redox properties. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [ABSTRACT FROM AUTHOR]

The potential energy surface information of the CH2CO + CN reaction is obtained at the B3LYP/6-311+G(d,p) level. To gain further mechanistic knowledge, higher-level single-point calculations for the stationary points are performed at the QCISD(T)/6-311++G(d,p) level. The CH2CO + CN reaction proceeds through four possible mechanisms: direct hydrogen abstraction, olefinic carbon addition–elimination, carbonyl carbon addition–elimination, and side oxygen addition–elimination. Our calculations demonstrate that R→IM1→TS3→P3: CH2CN + CO is the energetically favorable channel; however, channel R→IM2→TS4→P4: CH2NC + CO is considerably competitive, especially as the temperature increases (R, IM, TS, and P represent reactant, intermediate, transition state, and product, respectively). The present study may be helpful in probing the mechanism of the CH2CO + CN reaction. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 [ABSTRACT FROM AUTHOR]