Analysis of the ground-state band and a closely related intercalated band of 235(92)U143 by the two-revolving-cluster model with consideration of symmetric and antisymmetric resonance of the two dissimilar clusters.

Abstract

The reported ground-state band of 29325U143 extending from J = 7/2-to ½Y2-is found to be two intercalated bands, one beginning with 7/2-and the other with 9/2-, each with AJ = 2. Analysis by the two-resonating-cluster model leads to 3875 Da.fm2 for the moment of inertia for the first few levels, then increasing by centrifugal stretching. This value is interpreted by the structure p70n"12 for the central sphere with clusters p"1n"6 and pllnl5 with radius ofrevolution R = 8.55 fm. The major principal axis of the Poinsot ellipsoid is taken to be determined by an unquantized number K, with vector intermediate in orientation between L and J. The values of K are found by empirical analysis to equal L + 0.28, with the theory of rotation of the ellipsoid giving L + 0.28 for 7/2-, slowly decreasing to L + 0.251 for sY2-. The 7/2-band is based on odd values of L (negative parity) and the '/2-band on even values (positive parity). Negative parity for both bands is achieved by symmetric resonance of the two dissimilar clusters in the 7/2-band and antisymmetric resonance in the 9/2-band.The polyspheron model of nuclear structure (1) is based upon the idea (1, 2) that the shell-model orbitals can be hybridized into a set of localized ls orbitals, each of which can be occupied by no more than two protons and two neutrons to form spherons. The principal spherons are the helion, p2n2, and the triton, pn2, with the deuteron, pn, and others sometimes playing a part. The model has had considerable success in providing simple interpretations of many properties of nuclei. Levels of rotational bands have been analyzed by assuming that they correspond to revolution of a cluster about a central sphere (3-5). It has been reported recently by one of us (6) that 35 ground-state bands of lanthanon nuclei show a transition with increasing value of the angular momentum quantum number J from revolution ofa single cluster to revolution of two clusters, giving segments of superdeformed bands, and also (7) that 56 reported excited bands of lanthanon and Hg-Tl-Pb nuclei could be interpreted on the basis of the two-revolving-cluster model. The small energy differences of the levels of the reported ground-state band of 23IU143, extending from J 7/2-to 5Y2-, with AJ = 1 (8), led us to conclude that this band (which we found to be two intercalated bands with AJ = 2) is based on a superdeformed two-revolving-cluster model. The methods of analysis, both empirical and theoretical (vector-model theory, theory of rotational motion of a torus), are presented in the following paragraphs.The publication costs of this article were defrayed in part by pae )barge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact. Analysis of the Apparent Ground-State Band: Its Resolution into Two BandsThere are a reported 23 negative-parity energy levels from the ground state J = 7/2-to J = 5Y2-, with AJ = 1 (8 Table 1. For the 7/2-band the first three values ofthe moment of inertia calc...