The decay of hot and rotating compound nucleus 164 Yb * , formed in heavy ion reaction 64 Ni+ 100 Mo at both below-and above-barrier energies, is studied on the basis of the dynamical cluster-decay model (DCM) with effects of deformations and orientations of nuclei included in it. There is only one parameter in this model, namely the neck-length parameter, which varies smoothly with the temperature of the compound nucleus at both below-and above-barrier energies, and its value remains within the range of validity of the proximity potential. The emission of light particles (xn, x-neutrons, x = 1-4) as well as the energetically favoured intermediate mass fragments (IMFs) of both the light (5 A 2 20) and heavy (40 A 2 50) masses, together with the symmetric fission (SF) channel ((A/2) ± 20), is considered as the dynamical collective mass motions of preformed fragments or clusters through the barrier. The light-mass IMFs, the heavy-mass fragments (HMFs) and SF, constituting the fusion-fission (ff) cross-section, contribute only at above-barrier energies, and are compatible with the CASCADE analysis of experimental data. A best fit to data is obtained for two different neck-length parameters, one for light particles (LPs) and another for all other decay channels, the ff crosssection. The barrier height corresponding to the neck-length parameter for LPs gives 'barrier lowering' in a straightforward way for the best-fitted fusionevaporation cross-sections in DCM, and, in contrast to the (statistical model) analysis of experimental data, results in largest contribution for 1n emission. A further study is called for both the LPs and ff channels.

In this theoretical study, we establish an interrelationship between the nucleon-nucleon interaction potential and the nuclear fusion reaction cross-sections at low energies. The axially deformed self-consistent relativistic mean field with non-linear NL3 * force is used to calculate the density distribution of the projectile and target nuclei for fusion. The Wong formula is used to estimate the fusion cross-section and barrier distribution from the nucleus-nucleus optical potential for Nibased systems, which are known for fusion hindrance phenomena. The results of the application of the so obtained nucleus-nucleus optical potential for the fusion cross-section from the recently developed relativistic N N −interaction (R3Y) are compared with the well-known, phenomenological M3Y effective N N potential. We found a relatively good results from R3Y interactions below the barrier energies as compare to the M3Y potential concerning the experimental data. We also observe the density dependence on the nuclear interaction potential in terms of nucleon-nucleon optical potentials.

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While revising our paper, a reference to recent work on proximity potentials [1] was deleted and an error occurred in Eqs. (29) and (30). These equations should now be read asandThe results and conclusions of the original article remain the same.[1] I. Dutt and R. K. Puri, Phys. Rev. C 81, 064608 (2010);

Clustering phenomenon in nuclei is studied within the relativistic as well as non-relativistic mean field approaches, and also as a collective clusterization process in the decaying hot compound nucleus.

The decay of the hot and rotating compound nucleus 241 Pu * formed in the reaction 9 Be + 232 Th around the Coulomb barrier (≈42.16 MeV), at energies ranging from 37 to 48 MeV, is studied using the dynamical cluster-decay model (DCM) with the effects of static and dynamic deformations included. With the inclusion of dynamical deformations both the preformation probability P 0 and the tunneling probability P , and hence the cross sections, change considerably. The only parameter of the model, namely, the neck-length parameter, varies smoothly with excitation energy or temperature of the system both at above-and below-barrier energies, whose value depends strongly on the limiting angular momentum, which in turn depends on the sticking and nonsticking moments of inertia. The relative effect of static and dynamic deformations on the neck-length parameter R is also studied which indicates the reaction time scale for both static and dynamic choices of deformation. In addition, the exclusive role of angular momentum and "barrier modification" effects at sub-barrier energies are also addressed. Although calculated anisotropies are consistent with the results of Appannababu et al. [Phys. Rev. C 83, 067601 (2011)], no significant contribution of a noncompound nucleus in the form of incomplete fusion is seen on the basis of DCM calculations.

Materials with an intrinsic (ultra)low lattice thermal conductivity (k L ) are critically important for the development of efficient energy conversion devices. In the present work, we have investigated microscopic origins of low k L behavior in BaO, BaS, and MgTe by exploring lattice dynamics and phonon transport of 16 isostructural MX (M = Mg, Ca, Sr, and Ba and X = O, S, Se, and Te) compounds in the rocksalt (NaCl)-type structure. Anomalous trends are observed for k L in MX (M = Mg, Ca, Sr, and Ba and X = O, S, Se, and Te) compounds except for the MgX (X = O, S, Se, and Te) series in contrast to the expected trend from their atomic mass. The underlying mechanisms for such low k L behavior in large mismatch atomic mass systems, namely, BaO, BaS, and MgTe, are thoroughly analyzed. We propose the following factors that might be responsible for low k L behavior in these materials: (1) high mass contrast provides a phonon gap between the acoustic and optic branches; (2) softening of transverse acoustic (TA) phonon modes due to the presence of heavy element; (3) low-lying optic (LLO) phonon modes fall into the acoustic mode region and are responsible for softening of the acoustic phonon modes or enhancing the overlap between LLO (TO) and longitudinal acoustic (LA) phonon modes, thereby increasing scattering rates; (4) shorter phonon lifetimes; and (5) a relatively high density (ρ) and a large Gruneisen parameter (γ) leads to strong anharmonicity. Moreover, tensile strain causes a further reduction in k L for BaO, BaS, and MgTe through phonon softening and near ferroelectric instability. Our comprehensive study on 16 binary MX (M = Mg, Ca, Sr, and Ba and X = O, S, Se, and Te) compounds provides a pathway for designing (ultra)low k L materials through phonon engineering even with simple crystal systems.