Abstract:
The present thesis contains an account of some theoretical studies on silicon nano-systems. After a review of some uses and calculations silicon nanoclusters (SiNCs) a brief introduction to the theoretical methods used is given. Some preliminary calculations of the Egap by several methods are followed by calculations of polarizability and complex dielectric constants and refractive indices. For these we use two sets of systems: (i) a set of open silanes and (ii) and a set of sila-diamondoids. An anomalous behavior is observed in the frequency dependence of optical properties in the case of sila-diamantane and ascribed tentatively to the relatively more compact structure. The thesis concludes with a study of one-photon absorption (OPA) and two-photon absorption (TPA) of silicenes with substitutions, and some concluding remarks.
