Nuclear Quadrupole Resonance and the Electronic Structure of Gallium

摘要

An investigation of the nuclear quadrupolar coupling in solid Gallium metal is carried out with the aid of experiments on a single metallic crystal. Two physically inequivalent sites for the electroc field gradient tensor are found and the orientation of each set of principle axes is determmined. A previous measurement of the asymmetry parameter of the electric gradient tensor is described and an imprived value, 0.175 = 0.010 is reported. The asymmetry parameter may be obtained from the measurement of the splitting of the inner and outer pairs of the zeeman spectrum when the magnetic field lies in the principle XY plane. The error in the measurements arising from a neglect of the azimuthal dependence of the splitting in the XY plane is given. A theory of the origin of the field gradient tensor based upon p-type bonding of a Gallium atom with its first seven nearest neighbors predicts the quadrupolar coupling constant within 5% of the experimental value. The results suggest that the electronic structure may be described in the tight binding approximation. (Author)