Contains The First-principles Study Of The Planar Tetracoordinate Carbon Nanomaterials

The structures, stabilities, and electronic properties of the three types of novel compounds containing the planar tetracoordinate carbon (ptC) or quasi-planar tetracoordinate carbon (qptC) have been explored by the density functional theory (DFT). The three types of novel compounds are C3B2 sheet with multi-ptC, C3B2 nanotubes with multi-quasi-ptC and Cage-like macromolecular compounds with multi-qptC. The main contents and conclusions are listed as follows:1. Two-dimensional periodic C3B2 sheet and one-dimensional periodic C3B2 nanotube containing multi-ptC or multi-quasi-ptC have been constructed in this work. In the MS software DMOL3 module, by use of PBE gradient correction functional, double-numerical polarization basis sets (DNP) plus all e-GGA spin unrestricted calculation method, the structure, stability and electronic properties of the C3B2 sheet and C3B2 nanotubes were investigated. The results show that: between the structural stability of the C3B2 sheet and boron atoms have a great relationship and boron atoms played aσ-donating andπ-accepting role. C3B2 sheet is 0.84eV band gap semiconductor. The C3B2 nanotubes nature and curl way are relate in which armchair type nanotubes is a direct band gap semiconductor, zigzag nanotube is an indirect band gap semiconductor.2. The initial atomic structure models of the C36B24, C45B30, C54B36 cage-like macromolecules with 12,15,18 planar tetracoordinate carbons (ptC) are constructed. The structure study for C36B24, C45B30, C54B36 cage-like macromolecules and fullerene C60, C90clusters using ab initio calculations based on density functional theory is reported. The results show that C36B24, C45B30, C54B36 cage molecular symmetry are unchanged, ptC atomic position protrudes, the lowest frequency is 84,94, 82cm-1, HOMO-LUMO energy gap is 3.369,3.405,3.578eV. Ionization energy and electron affinity of the cage-like molecule C36B24 are 7.056eV and 1.543eV. Such cage-like molecules have rich chemical properties resembling C60, C90clusters.