Proposed nomenclature for helium allotropes

JAN 01, 1964

The following proposal is based on an earlier recommendfition by A. F. Schuch and R. L. Mills, dated September 1962, and on the considerations and agreements arrived at during a meeting held in the Queen Mary College, London, September 20, 1962, at which meeting nearly all research scientists interested in the question were in attendance. The proposal, moreover, has been approved by J. de Boer, Secretary of the Commission on Symbols, Units, and Nomenclature, of the International Union of Pure and Applied Physics.

DOI: 10.1063/1.3051372

J. G. Daunt

A. F. Schuch

R. L. Mills

Until 1953 it was not known that more than one allotrope of helium existed. In that year Dugdale and Simon reported the existence of two solid forms of ${He}^{4} .$ These are the α and β forms in Fig. 1. Then in 1961 Vignos and Fairbank showed that a third solid phase, $γ‐ {He}^{4},$ existed in a narrow region along the melting curve. At the Los Alamos Scientific Laboratory the three allotropic forms of ${He}^{3}$ shown in the figure were discovered. The structures of all these solid phases have been found by x‐ray and neutron diffraction studies and are listed in Table 1.

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References

1. J. S. Dugdale and F. E. Simon, Proc. Roy. Soc. (London) A218, 291 (1953).https://doi.org/PRLAAZ
2. J. H. Vignos and H. A. Fairbank, Phys. Rev. Letters 6, 265 (1961).https://doi.org/PRLTAO
3. E. R. Grilly and R. L. Mills, Ann. Phys. 8, 1 (1959).https://doi.org/ANPYA2
4. A. F. Schuch and R. L. Mills, Phys. Rev. Letters 6, 596 (1961).https://doi.org/PRLTAO
5. W. H. Keesom and K. W. Taconis, Physica 5, 161 (1938).
6. A. F. Schuch, E. R. Grilly and R. L. Mills, Phys. Rev. 110, 775 (1958).https://doi.org/PHRVAO
7. R. L. Mills and A. F. Schuch, Phys. Rev. Letters 6, 263 (1961).https://doi.org/PRLTAO
8. A. F. Schuch and R. L. Mills, Phys. Rev. Letters 8, 469 (1962).https://doi.org/PRLTAO
9. D. G. Henshaw, Phys. Rev. 109, 328 (1958).https://doi.org/PHRVAO

More about the Authors

J. G. Daunt. Ohio State University.

A. F. Schuch. Los Alamos Scientific Laboratory.

R. L. Mills. Los Alamos Scientific Laboratory.