P. Urbanowicz

Molecular orbital studies of harmonic vibrations of nitrobenzene in the gas phase and solution using semi-empirical, ab initio and density functional theory calculations

Abstract Semi-empirical PM3 and ab initio calculations were performed at the Hartree–Fock level of theory on nitrobenzene. Several basis sets were used and some calculations were performed within a density functional theory (DFT) using the B3LYP hybrid functional. The theoretically predicted NO2 group harmonic frequencies of nitrobenzene in the gas phase and solutions of low and high polarity using a dielectric continuum model were compared with the corresponding experimental FT-IR data. The results of these theoretical and experimental studies could provide deeper insight into the nature of the local structure of liquid nitrobenzene.

Electrical and Magnetic Properties of CuEu2W2O10 and Cu3Eu2W4O18

Magnetic susceptibility measurements showed both a weak response to magnetic field and a lack of the Curie-Weiss region for CuEu2W2O10 and Cu3Eu2W4O18 tungstates characteristic for the multiplet widths comparable to thermal energy. Magnetization measurements displayed the linear temperature dependence with the lower magnetic moment for Cu3Eu2W4O18 in comparison with CuEu2W2O10, indicating that the effect of the electric charges associated with the surrounding ligands can change the multiplet width of individual states. It is affecting the electrical properties of examined tungstates which reveal the insulating state and low relative permittivity εr ~ 29 in case of CuEu2W2O10 and the thermally activated p-type electrical conduction for Cu3Eu2W4O18 with the activation energy of 1.11 eV and the large value of εr ~ 217 above the room temperature.

Influence of Co Moment on Magnetic Properties of Co2Sm2W3O14 Tungstate

The Co2Sm2W3O14 compound crystallizes in the orthorhombic system, and melts congruently at 1443 K. The magnetic measurements showed that Co2Sm2W3O14 is a paramagnet in the temperature range 4.2-225 K showing both the residual magnetic interactions since the paramagnetic Curie-Weiss temperature   0 and the uncompensated temperature independent contributions of magnetic susceptibility since 0  0. The Brillouin fit of the Landé factor revealed an increase of the orbital contribution to the total magnetic moment of the compound what seems to be responsible for its hard and spontaneous magnetization at low temperatures.