Gm. Amalskii, EMPIRICAL REGULARITIES IN NUCLEAR ROTATIONAL SPECTRA AND A POSSIBLE MECHANISM OF FORMATION OF THE ROTATIONAL ANGULAR-MOMENTUM, Physics of atomic nuclei, 56(9), 1993, pp. 1190-1200
An empirical formula epsilon(N)(J) = epsilon0 sin2(pi Absolute value o
f J/N) proposed here gives a good description of the levels of the gro
und bands of strongly deformed nuclei with mass number A greater-than-
or-equal-to 100 up to energies epsilon(J) less-than-or-equal-to 5 MeV.
The expression contains one adjustable parameter N, which does not de
pend strongly on the charge of the nucleus, and a parameter epsilon0 i
s-approximately-equal-to 6.7 MeV which is common for all nuclei. The e
nergies epsilon(J) - epsilon(J0) of the levels of most rotational band
s of various nuclei with ground-state angular momenta J0 of the bands
are described well by the sequences epsilon(N)(R) - epsilon(N)(R0) wit
h R - R0 = J - J0, calculated by means of this expression, where R0 is
a second integer adjustable parameter of the band. In order to explai
n these empirical regularities, it is proposed to interpret the rotati
onal state of a deformed nucleus as a state with conserved orientation
of the symmetry axis of the nucleus aligned with the conserved projec
tion of the angular momentum. Arguments are given in favor of the assu
mption that the collective ''rotational'' angular momentum R with the
value Absolute value of R = (R(R + 1))1/2 and the integral-valued cont
ribution R to the conserved projection J of the total angular momentum
of the nucleus is generated by the closed tunnel current of pairs of
correlated nucleons.