Electron transport and optical properties of carbon nanostructures from first principles

Recent developments in ab initio studies of the nonlinear electron transport and optical properties of nanostructures are discussed. As examples of applications, results are presented for carbon atomic wires and single-walled carbon nanotubes. For the carbon atomic wires, strong nonlinearities in the I-V characteristics and conductance are obtained, and the role of interface chemistry and lead composition is demonstrated to be extremely important in determining its transport properties. For single-walled carbon nanotubes, explicit treatment of many-electron interactions shows that excitonic effects are dominant in these quasi-one dimensional systems and thus essential to explain the observed optical absorption spectra.