Finite-length models of metallic and semiconducting carbon nanotubes (CNTs) based on Clar sextet theory of aromatic systems are proposed. For metallic CNTs, the electronic properties of finite-length models converge monotonically to the values expected for quasi-monodimensional metallic systems. For semiconducting CNTs, the use of finite-length models as proposed in this work leads to a fast convergence of the electronic properties to the values expected for the corresponding infinite-length nanotube.

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Two-dimensional supramolecular arrays provide a route to the spatial control of the chemical functionality of a surface, but their deposition is in almost all cases limited to a monolayer termination. Here we investigate the sequential deposition of one 2D array on another to form a supramolecular heterostructure and realise growth, normal to the underlying substrate, of distinct ordered layers, each of which is stabilised by in-plane hydrogen bonding. For heterostructures formed by depositing terephthalic acid (TPA) or trimesic acid (TMA) on cyanuric acid/melamine (CA.M) we determine, using atomic force microscopy under ambient conditions, a clear epitaxial arrangement despite the intrinsically distinct symmetries and/or lattice constants of each layer. Structures calculated using classical molecular dynamics are in excellent agreement with the orientation, registry and dimensions of the epitaxial layers. Calculations confirm that van der Waals interactions provide the dominant contribution to the adsorption energy and registry of the layers.

We study the changes in electrodynamic responses due to Li insertion into layered a-MoO 3 . We compute electronic and dielectric properties, including the optical conductivity response of pure and lithiated oxides Li 2 MoO 3 , as a means to understand and reproduce the charge-discharge profiles observed in experiments.We unravel a 2-electron mechanism of Mo(VI) center reduction, which suggests Li substitution by divalent cations as a route towards cycling optimization. Along this line we provide a general paradigm for battery material characterization using first principles techniques based on optics, which can be advantageously used for example in high-throughput material screening approaches.

Electron transfer processes play a significant role in host-guest interactions and determine physicochemical phenomena emerging at the nanoscale that can be harnessed in electronic or optical devices as well as biochemical and catalytic systems. We have developed a novel method for qualifying and quantifying the electronic doping of single walled carbon nanotubes (SWNT) using electrochemistry and have established a direct link between these experimental measurements and ab initio DFT calculations. Metallocenes such as cobaltocene and methylated ferrocene derivatives were encapsulated inside SWNT (1.4 nm diameter) and the cyclic voltammetry (CV) performed. The electron transfer between guest-molecules and host-SWNT is measured as a function of shift in the redox potential (E1/2) . Furthermore, the shift in E1/2 is shown to be inversely proportional to the nanotube diameter. For the quantification of the amount of electron transfer from the guestmolecules on the SWNT, a novel method using coulometry was developed allowing the mapping of the density of states (DOS) and the Fermi level of the SWNT. Correlated with theoretical calculations, coulometry provides an accurate indication of n/p-doping of the SWNT.