[en] Clusters heavier than those observed in the cluster-radioactivity of heavy nuclei can not only be formed in superheavy compound nuclei but also be immediately expelled, because the clusterization energy is very great. This process differs from cluster-radioactivity and constitutes a new type of fission reaction. Its reality is confirmed by recent experimental observations. (author)

[en] A lot of information concerning the interaction laws between nucleons in the valence shells of trans-²⁰⁸Pb nuclei can be obtained from experimental mass tables. The proton-neutron interaction energy can be expressed by E_np = N_pN_n ε_np' where N_pN_n is the number of n-p couples in the valence shells, and ε_np' a weak, nearly constant interaction energy per n-p couple. Two methods are proposed for the calculation of E_np. In even-even nuclei, the integral 2p-2p interaction energy is given by E_2p-2p = -N_p(N_p -1)ε_2p-2p/2, where N_p is the number of proton pairs, and ε_2p-2p a weak, nearly constant interaction energy per 2p-2p couple. A similar relation holds for valence neutron pairs. The energy binding all the valence proton pairs to the ²⁰⁸Pb core is N_pσ-bar_2p, where σ-bar_2p is calculable in a simple way from Z = 84 to Z = 92; its value is independent of the number of pairs of nucleons of the other kind in the valence shells. A similar relation holds for valence neutron pairs. Similar laws hold in odd nuclei. The weakness of all these valence shell interaction energies, and the fact that the energy binding an unpaired proton to the ²⁰⁸Pb core of odd-Z nuclei decreases rapidly as N_p increases, explain several properties, which are briefly discussed, of trans-²⁰⁸Pb nuclei: repulsion between valence neutrons, feasibility of Oganessian reactions, shell internal energy, and reactivity of the valence nucleons

[en] Full text: There is no need of a repulsive potential in the amalgamation stage for explaining the small fusion cross sections. The repulsive potential proposed by A. Adamian et al. can advantageously be replaced by the affinity of the reaction of redissociation of the compound nucleus into its entrance-channel configuration. This reaction, which occurs after the penetration of the Coulomb barrier, is an equilibrium between dual and compact form of the compound nucleus, and the energy Q released in the dissociation is equal to the energy required for amalgamating. The total energy of the confined system being equal to the height B of the Coulomb barrier, the intrinsic excitation energy of the compact nucleus is equal to (B - Q). In the reaction 82Se+ 138Ba, the dissociation of 220Th releases 180.524 MeV, and B= 196.08 MeV. With an intrinsic excitation energy of 15.56 MeV, the confined compact 220Th has enough energy for emitting two neutrons ( S2n = 13.85 MeV). Thus the favored xn channel of fusion reactions can be precisely predicted. This new, mass-data-based model of fusion is completely parameter-free. In fusions leading to superheavy nuclei the redissociation energy (clusterization) becomes extremely great and can be equal to B or greater than B: Thus new phenomena can be observed, superheavy cluster- decay and cluster-fission. Refs. 3 (author)

[en] It was shown that the 'equatorial' a-emission of ternary fission can be considered as the a-decay of the double giant dipole resonance. The paper shows now that the equatorial ¹⁰Be emission can be interpreted as the ¹⁰Be-decay of the DGDR. But how can the 'polar' a-emission in ternary fission, or the isotropic emission of Be in incomplete fusion reactions such as ²³²Th + ⁴He at 200 MeV, be explained? The paper recalls that the formation of a ¹⁴C cluster in ¹⁴⁶Ba fragments is probably responsible for the recently discovered second mode of fission of ²⁵²Cf, and assumes, in analogy with the 1⁴⁶ Ba case, that less fragile clusters than carbon clusters are formed in other fission fragments, e.g. O-, Ne- (etc.) clusters in Ce-, Nd- (etc.) fragments, from the valence nucleons of their ¹³²Sn core, and that these clusters can be ejected in internal energy-rich collisions of vibrating complex fragment configuration. Several arguments are presented in favour of this new hypothesis. Both modes of cluster emission are new disintegration modes of the fission fragments themselves

[en] The so-called non-statistical Gamma.radiation emitted in the asymmetric fission of ²⁵²Cf can be interpreted as echoing the repercussions, in the doubly magic core ¹³²Sn, of the cataclysmic transfer of all, or almost all, of its 76 valence nucleons in rearrangement reactions of the diclusteric molecules involved in the process of asymmetric fission

[en] The apparent disappearance of odd-effects in the fission yields of Ba-Zr cold a-ternary mass splits, reported by Ramayya et al., is shown to be related to the anomal yield of the ¹⁴⁶Ba-¹⁰⁶Mo binary mass split, and can be interpreted as a proof of the role of the ¹⁴⁶Ba-¹⁰⁶Mo splitting in the second mode of fission described by Ter-Akopian et al

[en] Any heavy nucleus has a tendency to dissociate into a dinuclear system, made of core and cluster, having a definite Coulomb barrier and a definite internal energy. This allows a new description of fusion reactions, in which the excitation energy of the compound nucleus is made two parts, an intrinsic and an extrinsic excitation energy. For example, the yield of ²⁶²Bh formed in two different reactions depends on the intrinsic excitation energy of the compact compound nucleus ²⁶³Bh; the maximal yrast level obtainable in the gamma-deexcitation of two different levels of a nucleus formed at two different projectile energies can be the same, since it depends only on the intrinsic excitation energy after particle evaporation. The case of a negative affinity of dissociation will be discussed. Entrance-channel effects depend on intrinsic properties of the compound nucleus. Bohr's model of the compound nucleus must be reviewed: this revision is necessary for understanding the synthesis of superheavy elements. (orig.)

[en] An explanation is presented for the energy shift of the electromagnetic radiation de-exciting the first 2⁺ state of the ¹⁰Be ternary cluster accompanying the spontaneous fission of ²⁵²Cf, a shift found experimentally to range between 6 and 26 keV for selected mass splits: we show that relativistic effects furnish both the right sign and the right order of magnitude of this shift, and this holds both for the equatorial, low-energy LCP emission mode, and for the isotropic, higher-energy LCP emission mode. (orig.)

[en] Modern nuclear thermochemistry is more than a collection of Q values of nuclear reactions or transformations and than a table of atomic masses, and nuclear binding energies of nucleons and dinucleons. It is indeed possible to calculate all the various neutron-proton interaction energies and pairing energies of the valence nucleons and dinucleons, and to give a complete description of the energetic structure of the nuclei in their ground state. Even the process of nuclear fission can receive a better description. (author)

[en] If the interactions between valence nucleons are taken into account, the true value of the pairing energy in the valence shells of trans-²⁰⁸Pb nuclei appears to be 1184.9 keV for proton pairs and 1249.1 keV for neutron pairs; and a new representation of the E(4⁺)/E(2⁺) ratio of the first two excited states of these nuclei can be proposed, in which a parameter related to the shell internal energy is used instead of the P parameter of Casten et al. New results concerning the 4₁⁺ level of ²¹⁴Po are reported. The nuclei ²¹²Po, ²¹⁴Po, ²¹⁴Rn, ²¹⁶Rn, ²¹⁶Ra and ²¹⁸Ra are of the ''(j)²-like'' type