ABSTRACT
Spontaneous fission and alpha decay are both nuclear processes in which a parent nucleus A, Z is split in two fragments: A,Z, and A2Z2:
(I)
In this transformation the hadron numbers are conserved:
(2)
Fusion phenomenon is governed also by Equation 1, in which the arrow is reversed. In a symmetric process, A, = A2 , Z, = Z2 • Very often A, ¥- A2 , Z, ¥- Z2 ; for these
asymmetric phenomena mass and charge asymmetry parameters are conveniently defined
For the most probable split in fission of actinides one has 1Jz = 1JA> of the order of 0.176, but for a-decay of 202Po, 1Jz = 0.9756, 1JA = 0.962. In this last case, 1Jz ¥- 1JA because Z2 = N2 for a light, beta-stable emitted nucleus, but NzfZ 1 = I.536 for the heavy daughter
the alpha decay and to the new radioactivities of intermediate asymmetry, the macroscopic energies1·3 presented in Chapter 2 (LDM, FRNFM, andY+ EM) were developed only for a charge asymmetry equal to the mass asymmetry. Even in heavy-ion reactions with asymmetric partners in the input channel, many authors have assumed the same charge-to-mass ratio of two nuclei (Z/ A, = Zzf A2) by choosing one of the reaction partners to be off the line of beta stability. Other alternative was to consider realistic combinations, but to ignore the different charge-to-mass ratio.
