title: Electronic, bonding, and optical properties of 1d [CuCN]n (n = 1-10) chains, 2d [CuCN]n (n = 2-10) nanorings, and 3d [Cun (CN)n ]m (n = 4, m = 2, 3; n = 10, m = 2) tubes studied by DFT/TD-DFT methods.
abstract: The electronic, bonding, and photophysical properties of one-dimensional [CuCN](n) (n = 1-10) chains, 2-D [CuCN](n) (n = 2-10) nanorings, and 3-D [Cu(n)(CN)(n)](m) (n = 4, m = 2, 3; n = 10, m = 2) tubes are investigated by means of a multitude of computational methodologies using density functional theory (DFT) and time-dependent-density-functional theory (TD-DFT) methods. The calculations revealed that the 2-D [CuCN](n) (n = 2-10) nanorings are more stable than the respective 1-D [CuCN](n) (n = 2-10) linear chains. The 2-D [CuCN](n) (n = 2-10) nanorings are predicted to form 3-D [Cun (CN)(n)](m) (n = 4, m = 2, 3; n = 10, m = 2) tubes supported by weak stacking interactions, which are clearly visualized as broad regions in real space by the 3D plots of the reduced density gradient. The bonding mechanism in the 1-D [CuCN](n) (n = 1-10) chains, 2-D [CuCN](n) (n = 2-10) nanorings, and 3-D [Cu(n)(CN)(n)](m) (n = 4, m = 2, 3; n = 10, m = 2) tubes are easily recognized by a multitude of electronic structure calculation approaches. Particular emphasis was given on the photophysical properties (absorption and emission spectra) of the [CuCN](n) chains, nanorings, and tubes which were simulated by TD-DFT calculations. The absorption and emission bands in the simulated TD-DFT absorption and emission spectra have thoroughly been analyzed and assignments of the contributing principal electronic transitions associated to individual excitations have been made.
authors.affiliation: Department of Chemistry, Laboratory of Inorganic and General Chemistry, University of Ioannina, 451 10, Ioannina, Greece.
authors.forename: Athanassios C
authors.initials: AC
authors.lastname: Tsipis
authors.affiliation: Department of Chemistry, Laboratory of Inorganic and General Chemistry, University of Ioannina, 451 10, Ioannina, Greece.
authors.forename: Alexandros V
authors.initials: AV
authors.lastname: Stalikas
mesh_terms: D003300:Copper / Q000737:chemistry*; D003486:Cyanides / Q000737:chemistry*; D004583:Electrons; D055095:Optics and Photonics; D011789:Quantum Theory
chemical_list: D003486:Cyanides; D003300:Copper; C057807:copper(II) cyanide
keywords: DFT; copper cyanide chains; copper cyanide nanorings; copper cyanide tubes; photophysics; stacking interactions; time-dependent density-functional theory