Features of Metal and Semiconductor Nanoparticles

First of all, electronic structure of nanoparticles was discussed. The influence of the size of particle on its electronic structure is determined by the nature of bonds in the particle lattice. In the lattice of molecular crystal intermolecular bonds cause only minor alterations in an electronic structure of molecules and are localized between the nearest neighbors in such lattice. In the lattice of inorganic crystal with purely ionic bonds the interaction of ion with medium is also localized in small space of the several coordination spheres surrounding an ion in the lattice. The transition of ion in the excited state gives essential disturbance of ionic lattice only in this space. 

the interaction between structural entities of molecular and ionic crystals does not lead to appreciable delocalization of electrons strongly bonded to these entities. Therefore, the electronic structure of molecular and ionic crystals is practically not influenced by the size of such crystals. Size effects arise only in M/SC crystals with covalent (or at least partly covalent) bonds and depend on a relationship between the crystal size a and the length of delocalization (or, otherwise, electronic correlation) for valent electrons in a lattice. 

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