Helion

Summary.—The assumption that atomic nuclei consist of closely packed spherons (aggregates of neutrons and protons in localized Is orbitals—mainly helions and tritions) in concentric layers leads to a simple derivation of a subsubshell occupancy diagram for nucleons and a simple explanation of magic numbers. Application of the close-packed-spheron model of the nucleus to other problems, including that of asymmetric fission, will be published later.13... 

The nature of spheron-spheron interactions is such that maximum stability is achieved when each spheron ligates about itself the maximum number of neighbors, to produce a nucleus with a closest-packed structure. A simple argument (12) leads to the conclusion that the spherons in a nucleus are arranged in concentric layers. The packing radius of a spheron varies from 1.28 f for the dineutron to 1.62 f for the helion. The radius (to nucleon density half that of the inner region) of the largest nucleus is 6.8 f... 

A4/ f), four times the helion radius. The thickness of the nuclear skin corresponds to the nubbled surface of the outer hemispheres of an outer layer of spherons. In a large nucleus the region within the outer layer would be lined with another layer of spherons, in contact with the outer layer, and within this layer there might be a central spheron or layer of spherons. 

Let us consider the nucleus 44Ru3o. As discussed above, it is assigned 26 spherons, of which 22 are in the mantle and four in the core. From Fig. 3 we might assign 37 protons to the mantle and seven to the core. This assignment gives a mantle of 11 helions and 11 tritons and a core of three helions and one triton. 

Structures of this sort, with a mantle of helions and a core of neutrons, have minimum Coulomb energy. We may expect these structures to have the minimum neutron excess compatible with stability any more protons would be forced from the mantle into the core. In fact, 44RuB2 has the largest atomic number for which N — Z equals 8 for a stable isotope. 

It is seen that, in accordance with the foregoing argument, the low-N ends of these horizontal lines lie close to the curve (mean deviation, 1). The conclusion may be drawn that the structures of stable nuclei involve a significant contribution of structures with a pure neutron core and a pure helion or nearly pure helion mantle. 

An ellipsoidal nucleus with two spherons in the inner core has major radius greater than the minor radii by the radius of a spheron. about 1.5 f, which is about 25 percent of the mean radius. The amount of deformation given by this model is accordingly in rough agreement with that observed (18). In a detailed treatment it would be necessary to take into account the effect of electrostatic repulsion in causing the helions to tend to occupy the poles of the prolate mantle, with tritons tending to the equator. 

In this assignment the assumption is made that the 22 helions of the mantle occupy the end regions of the highly deformed nucleus, as a result of their strong Coulomb repulsion. 

The name helion is used for the alpha particle L. Pauling, Nature 201. 61 (1964). 

Garro-Helion F, Guibe F (1996) J Chem Soc Chem Commun 641... 

Since the alpha-ray impacts shattered only a minute proportion of the total number of atoms of boron, aluminum, or magnesium, the chemical identification of the products was extremely difficult. These indefatigable workers, however, accomplished even this. Although it would have been impossible to identify the products simply by ordinary chemical means, the Joliots were able to take advantage of the radioactive nature of the products formed. Since they had good reason to believe that the boron atom had captured a helion and ejected a neutron and that the new element was therefore probably an isotope of nitrogen, they heated some bombarded boron nitride with caustic soda and found that the liberated... 

M. and Mme. Joliot-Curie showed that the magnesium atom, when similarly bombarded, also captures a helion and emits a neutron, as follows ... 

D. R. Corson, K. R. Mackenzie, and E. G. Segre prepare element 85 (astatine) by bombarding bismuth with helions. W. Minder and Hulubei and Cauchois independently give evidence for the existence of element 85 in the decay products of radon. 

Trade Names. Heliofolal (H R), Helional (IFF), Aquanal (Quest), Heliobouquet (Takasago). 

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