Electronic structure

Within the Green's function approach to the multiple scattering theory, we present a different formalism for the screened Korringa-Kohn-Rostoker (KKR) scheme. In addition, we investigate the convergence properties of the screened KKR by performing total energy and density of states calculations for a fcc copper. Finally, we introduce a new approach to (near) tight binding calculations of the screened tau-matrix that yields total energies within the desired accuracy.

The presence of multiply bonded dimetal units in materials offers opportunities for tuning properties of solids. Materials containing molybdenum-molybdenum quadruple bonds have recently begun being reported. This thesis reports the products of the reactions of dimethyl sulfide (DMS), acetonitrile (ACN) and acetate complexes, Mo2CI4(DMS)4, Mo2(ACN)10ABF4, and Mo2(0Ac)4
with 2,2';6,2"-terpyridine, 4'-phenyl 2,2';6,2"-terpyridine, 2,3,5,6-tetrakis (alpha-pyridyl) pyrazine and 1,3-bis(4-methylimino)isoindoline. Among these ligands, 2,3,5,6-tetrakis (alpha-pyridyl) pyrazine may lead to linear arrays of metal-metal bonds as well as other ordered structures. 1H-NMR, electronic absorption, and infrared data will be quoted to support any structural assignments.

This research is devoted in part to investigating the electronic structure of benzene, which will help to provide a foundation for understanding its behavior. Absorption and magnetic circular dichroism (MCD) data were collected for benzene and deuterated benzene in the vacuum ultraviolet region of the electromagnetic spectrum from 67,870 cm^-1 to 67,155 cm^-1 (8.415 eV to 8.326 eV). MCD data, when considered along with absorption data, gives information about the symmetry designations of electronic transitions. It is concluded that benzene and deuterated benzene each show transitions to pz-type and several f-type Rydberg orbitals in this spectral range. In addition, several Fortran computer programs have been developed to aid in the determination of these orbital symmetries.

The band structure, density of states, Fermi surface, bulk modulus and heat of formation were calculated for beta prime-NiAl using the SCF-LMTO-ASA method. The equilibrium lattice constant was also determined by minimizing the total energy. The angle-resolved and x-ray photocurrents from the valence bands were determined using the NEWPOOL and XPSI codes and the calculated spectra were compared with recent experimental measurements. In the former case, the calculations were carried out for the (001) surface using s-polarized light and included the experimentally observed relaxations of the top two layers with an Al termination. The overall agreement between the theoretical and experimental spectra is good, indicating that self-energy effects are not large.

This research is a preliminary investigation into the electronic transitions of Propylene. This investigation will concentrate on understanding the techniques for smoothing and calculating Gaussian fits for the experimental data. This will include knowledge of the symmetry operations for the propylene molecule and the "allowed" electronic transitions for further application to the propylene spectrum in the vacuum ultraviolet. Understanding the symmetry of the molecule and the observed absorption and magnetic circular dichroism spectra is necessary for later labeling the electronic transitions.