X-ray absorption measurements of high resolving power for potassium, which is expected to show wider departure from free electrons, have been carried out by Platt. " The X edge investigated shows quite close agreement with his theoretically predicted absorption which was based on the assumption that the electrons are free. No evidence existed to show an energy gap. This, of course, is at best supporting evidence of the ! non-existence of a gap in potassium since gaps "J.B.Platt, Phys. Rev. 69, 337 (1946). may exist which could be completely masked by the eigenvalue dependence upon wave vector direction. ACKNOWI EDGMENTS The authors are indebted to Dr. %.A. Bowers for permission to publish his results on the five additional states shown in Table IV and also wish to thank Dr. Bowers for continuing the application of the method when the war interrupted the work.

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Using the Bodnar model, the effective mass, density of states, and g-factor of Cd,As, are calculated.It is found that the g-factor is considerably more anisotropic than the effective mass, but decreases sharply with energy in all directions.Kous avons calculk, A partir du modde de Bodnar, la masse effective, le densiti? d'6tats e t le facteur g de Cd,As,. Nous trouvons que le facteur g est beaucoup plus anisotrope que la masse effective, e t diminiie rapidement en fonction de l'knergie pour toutes les directions cristallographiques.