SHELL CLOSURE AT THE TOUCHING POINT OF NUCLEAR FRAGMENTS

Shell correction energy of the fission fragments remains practically u nchanged when the separation distance increases from the sum of their radii up to infinity. The variation with mass asymmetry of the total d eformation energy at the touching point configuration shows the valley s corresponding to different decay modes, which are produced when the two proton and/or the two neutron numbers are magic or almost magic. W e present a contour plot of the deformation energy of the proton-rich alpha-emitter Te-106, showing for the first time the alpha-decay valle y. Different valleys mainly due to the doubly magic nuclei Sn-100,Sn-1 32, Pb-208, and other magic numbers, are illustrated by plotting the d eformation energy at the touching point versus the proton number of th e fragment, for the following parent nuclei: Te-106; Ce-116; Po-212; T h-228; Fm-258, and Fm-264.