MAGNETIC
MOMENTS INis that the individual atomic moments remain nearly constant throughout. Thus, the Fe moment remains within 10% of 2.8 ix B in both the Pd-Fe and Ni-Fe systems over a concentration range for which the average number of electrons per atom varies from 10-9. A similar property may be ascribed to the other atoms with characteristic moment values of 1.8 /*# per Co, 0.6 IIB per Ni and 0.4 JJLB per Pd. This atomic character of the moments in these face-centered cubic systems may well be explained by a partially localized-partially itinerant model. In this model the splitting of the d wave functions of t 2g and e g symmetry is accomplished not by a true crystal held effect, but rather by the overlap properties in this crystal structure of the two types of wave functions. The strongly overlapping t 2g functions are assumed to form a conventional band, and the fractional moments are attributed to exchange splitting in that band. The e g type functions do not *
The differential angular distributions of photoelectrons emitted in the formation of various ionic states have been determined for Ar, Kr, Xe, H2, N2, and O2. Where possible several photon energies have been employed, the 21.21-eV He resonance line and the 16.67- and 16.85-eV Ne resonance doublet. In most cases the angular dependence for the photoelectron emission can be described by a function of the form 1 + βP2(cosΘ). For certain of the rare gases ionized by the Ne resonance doublet large deviations from this prediction were obtained. These deviations are related to the energy of the outgoing electron and the structure of the ionic species formed.
An ion source is described which produces beams of ions of both high and low vapor pressure materials. The source has the following characteristics which make it suitable for accelerator applications or laboratory ion beam experiments where the large size and complexity of isotope separator ion sources would be a disadvantage: (1) small size, (2) simplicity of construction and operation, (3) long filament life, (4) high charge utilization efficiency, (5) wide operating temperature range, (6) relatively modest power requirement, (7) ability to operate efficiently on either gas or solids. The source operates by electron bombardment ionization of the vapor of the charge material. The vapor is obtained by heating the charge to a sufficiently high temperature to achieve the proper source operating pressure. A unique feature of this source is the combination of the discharge chamber and charge container into one chamber. The operating temperature range of the source is from approximately 300 to about 1600°C. Beams of Zn+, Al+, Cu+, Ag+, Au+, and Fe+ ions have been produced which contain but a small percentage of impurity ions. The charge material in all these cases has been the pure metal.
Electron capture, electron loss, and ionization have been studied for aluminum and iron ions and atoms passing through N2, O2, and Ar. The experiments, which took place in three separate laboratories, had available the energy range from 5 keV to 2.5 MeV. In addition to presenting the cross sections and the methods employed, the paper contrasts the effects of projectile particles having low first and second ionization potentials with those of the more usually studied projectiles having ionization potentials comparable with those of the target gas. Of particular interest is the comparison of charge-transfer-versus ion-stripping probabilities. The results are compared with some of the present approximate theories.
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