Temperature-dependent binding energies in a dynamical cluster-decay model applied to the decay of hot and rotating56Ni*

Abstract

The dynamical cluster-decay model (DCM), a nonstatistical description developed by Gupta and collaborators to account for the decay studies of excited compound nuclei formed in low-energy reactions has been applied to study various reactions. One of the main ingredient of the model is the use of temperature-dependent binding energies. In the present work, the effect of temperature-dependent binding energies in the model is analyzed. In earlier works on the DCM, the temperature-dependent liquid drop energy from Davidson et al.'s work [N. J. Davidson, S. S. Hsiao, J. Markram, H. G. Miller, and Y. Tzeng, Nucl. Phys. A 570, 61 (1994)], with two of its constants refitted for each isotopic chain to reproduce ground-state experimental binding energies, is used. In this work, the temperature-dependent binding energy formulas of Krappe [H. J. Krappe, Phys. Rev. C 59, 2640 (1999)] and Guet et al. [C. Guet, E. Strumberger, and M. Brack, Phys. Lett. B 205, 427 (1988)] are used in the DCM without any refitting of the coefficient of the liquid drop needed to study the decay of the hot and rotating 56 Ni * system formed in the 32 S + 24 Mg reaction at two incident energies, E c.m. = 51.6 and 60.5 MeV. The use of Krappe's formula results in the explicit preference of a four-nucleon transfer, indicating a strong minima in the potential energies corresponding to α-structured nuclei as well as exhibiting structural effects in the preformation calculations favoring α-structured nuclei. The overall cross sections for the light particles and intermediate mass fragments are nicely reproduced by the use of Krappe's formula. However, the individual channel cross-sections exhibit a strong distribution only for α nuclei, and for other fragments the results are lower by a factor of 2 to 3. The use of Guet et al.'s formula though does not show any explicit structure effects in the potential energy calculations or the preformation calculations; the overall cross sections calculated for light particles and intermediate mass fragments compare well with the experimental data. The results of individual channel cross-sections, however, do not exhibit any explicit preference for the α-structured nuclei; rather, the individual channel cross sections decreases with an increase in the mass number of the fragments. The calculated average kinetic energies using both formulas for the favored α fragments compares well with experimental values. Without any refitting of the coefficients of the temperature-dependent binding energies, the DCM works out well and the explicit preference of α structure depends mainly on the choice of formula used.

Role of neck-length parameter in dynamical cluster-decay model for the decay of $^{56}{\rm N}{{{\rm i}}^{*}}$

“…. In DCMʼs earlier calculations [12,14], α c = 0.4 is used. Earlier, we have studied [15] the role of α c (varied from 0.4 to 0.8) for the decay of Cu 59 .…”

“…Using DCM, this reaction has been first studied within a renormalization procedure [11] and later [12] has been studied for the actual cross-sections of LPs and IMFs by incorporating temperature (T) dependent binding energy formula of Davidson et al [13]. Recently, we have studied [14] the same reaction for the use of different T-dependent binding energy formulae. In [14], we have taken a different neck length parameter values for LPs and IMFs, our obtained results are comparable with the experimental data only for α-structured nuclei but not for all the fragments.…”

“…Recently, we have studied [14] the same reaction for the use of different T-dependent binding energy formulae. In [14], we have taken a different neck length parameter values for LPs and IMFs, our obtained results are comparable with the experimental data only for α-structured nuclei but not for all the fragments. Further, we have extended our study [15], by incorporating Tdependent Wigner and pairing energies and the role of α c for the decay of .…”

“…In the present work, as a sequel to our previous studies, with the incorporation of all these reformulations in the extended DCM, the + S Mg . Here, the role of neck length parameter is fitted for the individual fragments in order to achieve better fit with the available experimental data, which is not considered in the previous work [14].…”

Isotopic Ratio, Isotonic Ratio, Isobaric Ratio and Shannon Information Uncertainty

“…In the free energy based theories describing the HICs above the Fermi energy, the yield of a fragment follow the exponential function, which is mainly decided by the free energy, the chemical properties of the source, and temperature [7,11,[35][36][37][38]. In the ratio of fragment yield, the cancelation of some terms makes it possible to study the retained terms in the exponential function, and specific physical parameters can be studied.…”