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Knight shifts, Kv, of the V 51 isotope have been measured in binary alloys of V with Ti, Cr, and Tc. The shifts, KTC, of the Tc" nucleus have been measured over the whole composition range in the V-Tc system together with corresponding magnetic susceptibilities. The results on these bcc alloys indicate that the rigid band approximation is valid and nearly all electrons outside the closed 3p or 4/> shell form a common conduction band with admixtures of s and non-5 electronic states. Furthermore, these data augmented by electronic specific-heat measurements indicate that the proportion of electrons having s and non-s character changes with electron concentration within this common conduction band.

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Nuclear-magnetic-resonance properties of the V 51 and Nb 93 isotopes and magnetic susceptibilities are reported for V-Nb alloys. The magnetic susceptibility of V-Nb alloys decreases from 287X10 -6 emu/mole for pure V to 225 X10~6 emu/mole at 90 at.% Nb. The values of the square root of the nuclear spin-lattice relaxation rate (TiT)~1 /2 increase from pure V with increasing Nb concentration; (TiT)~1 /2 =1.12 (sec °K)" 1/2 for V and (TiT)-*t*=1.5S (sec °K)~1/ 2 for the V-90 at.% Nb alloy. The V 51 Knight shift increases from 0.564% in pure V to 0.602% in the 60 at.% Nb alloy, and then decreases slightly with increasing Nb concentration. The Nb 93 Knight shift decreases from 0.821% in pure Nb to 0.688% in the 30 at.% Nb alloy, and then increases with increasing V content. The results are compared with that of other V and Nb transitionmetal alloys. It is found that the simple rigid-band model is inadequate to interpret the composition dependence of the NMR and susceptibility data.

The equilibrium charge distribution between substances in contact is calculated in the one-dimensional approximation for metal-insulstor and insulator-insulator contacts. The direction of charge transfer is such as to equalize the Fermi levels, and the magnitude of charge transferred depends on the positions of the energy bands in the substances in contact. For example, in an insulator it is possible to have a large charge density (∼ 10 11 esu) within a thin layer (∼ 10 -8 cm.) or a small charge density (∼ 10 -1 esu) in a thick layer (∼ 10 -1 cm.), to give the same potential shift (∼ 1 ev), depending on the relative position of the bands. The energy levels in most insulators of high resistivities are too poorly known to allow strict quantitative comparison with experiment, but the results permit a semiquantitative explanation of some observations on static electrification.

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LAMThe spin-lattice relaxation time, T h associated with the V 51 and Tc" nuclei in the V-Tc binary alloy system has been measured over a range of compositions at room, liquid-nitrogen, and liquid-helium temperatures. The quantity T\T (T = absolute temperature) is strongly composition-dependent, but only slightly temperature-dependent, indicating that the predominant relaxation path is via conduction electrons. Of the possible terms contributing to conduction-electron relaxation, that due to the orbital motion of the d-band electrons is believed predominant.