Nuclear cluster decay

Bogumil Jeziorski received his M.S. degree in chemistry from the University of Warsaw in 1969. He conducted his graduate work also in Warsaw under the supervision of W. Kolos. After a postdoctoral position at the University of Utah, he was a research associate at the University of Florida and a Visiting Professor at the University of Waterloo, University of Delaware and University of Nijmegen. Since 1990 he has been a Professor of Chemistry at the University of Warsaw. His research has been mainly on the coupled-cluster theory of electronic correlation and on the perturbation theory of intermolecular forces. His other research interests include chemical effects in nuclear beta decay, theory of muonic molecules and relativistic and radiative effects in molecules. 

His research field is nuclear theory reactions, clustering, cluster decay and light exotic nuclei. He is a coauthor of the monograph Structure and Reactions of Light Exotic Nuclei (2003). 

The value of the critical nuclearity allowing the transfer from the monitor depends on the redox potential of this selected donor S . The induction time and the donor decay rate both depend on the initial concentrations of metal atoms and of the donor [31,62]. The critical nuclearity corresponding to the potential threshold imposed by the donor and the transfer rate constant value, which is supposed to be independent of n, are derived from the fitting between the kinetics of the experimental donor decay rates under various conditions and numerical simulations through adjusted parameters (Fig. 5) [54]. By changing the reference potential in a series of redox monitors, the dependence of the silver cluster potential on the nuclearity was obtained (Fig. 6 and Table 5) [26,63]. 

The transient Ag3 + ion have an intense absorption spectrum with two maxima, at 310 and at 265 nm. Its second-order decay leads to the cluster Ag4 +. Under total reduction conditions the neutral dimer Ag2 is observed at 275 and 310 nm. The optical transitions of low-nuclearity silver oligomers, the rate constants, and the extinction coefficients are derived from adjustment between experimental (Fig. 2, bottom) and calculated absorption spectrum evolution. An even number of atoms favors the high stability of the magic hydrated clusters Ag4 + (275 nm), Agg + and possibly Agi4 + (Fig. 2, top). After a longer time, the plasmon... 

The value of the nuclearity of this critical cluster enabling transfer from the monitor depends on the redox potential of the selected donor, S . We studied electron transfer to silver clusters from the decay of different electron donors,... 

In most samples the H spin-lattice relaxation rates are exponential and identical for both hydrogen sites that are observed in the free induction decay. This result is probably a consequence of the rapid nuclear spin diffusion process of the H nuclear magnetization to the neighborhood of the Hj sites. Reimer et al. (l9Slc) have measured spin - lattice relaxation rates by a technique that suppresses the nuclear spin diffusion processes (the so-called T iy technique). In these measurements one observes a nonexponential decay, as would be expected because those hydrogen atoms closest to an Hj molecule will relax faster in the absence of rapid spin diffusion. These Tly experiments also indicate that the narrow H NMR line has a relatively faster relaxation rate, which indicates the presence of a greater density of H2 molecules in this phase than in the clustered (broad NMR line) phase. 

Use of a surfactant allows solubilization of the polyoxometalate cluster K6[Vi5As6042(H20)] 8H20 (V15) in the organic solvent chloroform. Spin echo measurements revealed a phase memory time of Tm = 340 ns, which was attributed to resonances in the 5 = 3/2 excited state of the cluster [166]. No quantum coherence was detected in the pair of 5 = 1/2 ground states [151]. By measurement of the z-magnetization after a nutation pulse, and a delay to ensure decay of all coherences, Rabi oscillations were observed. From the analysis of the different possible decoherence mechanisms, it was concluded that decoherence is almost entirely caused by hyperfine coupling to the nuclear spins. 

Abstract In this chapter, four topics are treated. (1) Fundamental constituents and interactions of matter and the properties of nuclear forces (experimental facts and phenomenological and meson-field theoretical potentials). (2) Properties of nuclei (mass, binding energy, spin, moments, size, parity, isospin, and characteristic level schemes). (3) Nuclear states and excitations and individual and collective motion of the nucleons in the nuclei. Description of basic experimental facts and their interpretation in the framework of shell, collective, interacting boson, and cluster models. The recent developments, few nucleon systems, and ah initio calculations are also shortly discussed. (4) In the final section, the a- and P-decays, as well as the special decay modes observed far off the stability region are treated. 

The clustering phenomenon is a dramatic manifestation of the shell structure at very large deformations. From such a di-nuclear system one may expect strong fission decay to the components, similarly to the case of the enhanced a decay of light a + core nuclei above the a -i-core threshold. 

In the following, exotic nuclear decay modes of heavy nuclei, cluster radioactivities, delayed fission, and spontaneous fission (SF) together with the recent progress on deformation paths toward fission are briefly introduced. 

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