Electronic Structure, Bonding and Optical Spectrum of MgB2

This paper contains both recently published and original results concerning the electronic structure, bonding and relevant properties of (Mg-Al)B2. We analyse the electronic structure formation of bulk and surface states, study the nuclear spin-lattice relaxation rates, compare the theoretical and experimental estimates of the density of states at the Fermi level, and review the electron-phonon coupling calculations. The analysis of optical properties of MgB2 and AlB2 is also provided.