Investigation of empirical heat capacity in hot-rotating A ∼ 200 nuclei

Xuan, Tran Dong; Hưng, Nguyễn Quang; Le, Thi Quynh Huong; Vu, Duc Cong; Anh, Nguyen Ngoc

doi:10.1088/1361-6471/ac8568

Cited by 4 publications

(5 citation statements)

References 34 publications

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“…For instance, the shell-correction values significantly affect the computed heat capacity (see e.g. figure 7 of [26]), noticing that the shell corrections taken from various sources might significantly differ. Considering 153 Sm as a showcase, its shell correction is determined to be 2.84 MeV using Myers-Swiatecki mass formula [42], 3.6784 MeV using the Mengoni-Nakajima one [43], but only 0.95 MeV within the finite-range droplet macroscopic and the folded Yukawa singleparticle microscopic nuclear-structure models [44], and 1.484 MeV within the systematic investigation of Egidy et al [39], in which a traditional liquid drop macroscopic formula is involved.…”

Section: The Nuclear Level Densitymentioning

confidence: 99%

“…where ρ(E i ) is the total NLD at a given excitation energy E i and δE i is the energy bin. The latter is chosen to be 50 keV in the present work because it is appropriate, as demonstrated in [26]. Reducing δE i changes the calculated TQs insignificantly while increasing the computation times.…”

Section: Calculation Of Thermodynamic Quantities Within the Canonical...mentioning

confidence: 99%

“…Considering their importance and universality in various domains, as partly discussed above, the TQs of various nuclei have been determined, e.g. 56−57 Fe [18], 93−98 Mo [15,19,20], 116−117 Sn [21], 148−149 Sm [22,23], 161−163 Dy [24], 166,167 Er [25], some hot rotating nuclei at A ∼200 [17,26,27], 231−233 Th and 237−239 U [28]. Literally, two primary approaches have been utilized to determine the nuclear TQs, namely the canonical ensemble (CE) and microcanonical ensemble (MCE).…”

Section: Introductionmentioning

confidence: 99%

“…In practice, the MCE has advantages thanks to its simple formalism, resulting in its ability to extract the empirical TQs from experimental NLD (for details, see e.g. [24][25][26]). For instance, Dey et al [7] indicated a possible signature of pairing reentrance at excitation energy below 1 MeV by studying the proton entropy excess of five pairs of nuclei, whose mass ranges from medium to heavy regions based on the entropy derived by using the MCE.…”

Section: Introductionmentioning

confidence: 99%

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Systematic investigation on semi-empirical thermodynamic quantities of excited nuclei using canonical ensemble

Tran,

Phan,

Nguyen

et al. 2024

J. Phys. G: Nucl. Part. Phys.

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Semi-empirical thermodynamic quantities (TQs) of 78 nuclei ranging from $^{43}$Sc to $^{243}$Pu have been systematically investigated in the temperature region below 1 MeV using the thermodynamic canonical ensemble. The latter is carried out by taking into account the experimental nuclear level density (NLD) data measured using the Oslo method for the low-excitation region below the neutron binding energy $B_n$ combining with the back-shifted Fermi gas NLD model for the excitation energy from $B_n$ to about 250 MeV. In particular, the uncertainty of the TQs propagating from the fluctuation of the experimental NLD data has been, for the first time, calculated. The results obtained indicate that the uncertainty of TQs due to the experimental NLD is incomparable with the changes caused by the nuclear structure effects. The free energy of even-even nuclei behave differently from that of odd-$A$ ones. The total energy in the \rev{low-temperature region below $T_E \simeq 0.4-0.6$ MeV for medium-mass nuclei and $T_E \simeq 0.2-0.4$ MeV for heavy-mass ones slowly varies. When temperature is from $T_E$ to 1 MeV, the total energy} increases extremely faster than the increase of temperature, exhibiting the constant-temperature behavior. The entropy exhibits an abrupt change in their slope at \rev{$T_S \simeq 0.2-0.4$ MeV} in medium-mass nuclei and \rev{$T_S \simeq 0.5-0.6$ MeV} in heavy-mass ones. \rev{The existence of $T_E$ and $T_S$ has been interpreted due to the breaking of the first Cooper pair.} Finally, the heat capacity shows strongly pronounced $S$-shape in nuclei belong to rare-earth region. \rev{The temperatures defined at the center of the $S-$shaped heat capacities, which are known to closely relate to the critical temperature of the pairing phase transition $T_C$, are quite close to those theoretically predicted, namely $T_C \approx 0.5\Delta-0.6\Delta$ with $\Delta = 12A^{-1/2}$ being the empirical pairing gap at zero temperature.} The semi-empirical TQs obtained in the present work can be, therefore, a reliable data source to test and/or validate many nuclear thermodynamical models and to examine some nuclear structure properties such as pairing and deformation.

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Section: The Nuclear Level Densitymentioning

confidence: 99%

Section: Calculation Of Thermodynamic Quantities Within the Canonical...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Systematic investigation on semi-empirical thermodynamic quantities of excited nuclei using canonical ensemble

Tran,

Phan,

Nguyen

et al. 2024

J. Phys. G: Nucl. Part. Phys.

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“…To overcome this drawback, one must use the theoretical NLD whenever the experimental NLD data is missing. The back-shifted Fermi gas (BSFG) NLD model, which is the most widely used phenomenological model of NLD, is often employed for this purpose [11,13]. Fitting the BSFG formula to the experimental NLD data gives the most reliable values for its free parameters.…”

Section: Introductionmentioning

confidence: 99%

Updated heat capacities of $^{161-164}$Dy nuclei

Xuan

Nguyễn

et al. 2023

Comm. in Phys.

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This work presents the updated heat capacities of $^{161-164}$Dy nuclei in the nuclear temperature region from 0 to 1 MeV. The updated heat capacities are obtained within the canonical ensemble method making use of the most recent and recommended experimental nuclear level density (NLD) data together with those calculated within the back-shifted Fermi gas (BSFG) model with energy-dependent parameters. By comparing the updated heat capacities with the un-updated ones, which are obtained by using the old experimental NLD data and the BSFG with energy-independent parameters, we found that the updated and un-updated heat capacities are almost identical at low temperature, but differ from each others at high temperature. This discrepancy can be interpreted by the damping of nuclear shell structure with increasing the excitation energy. Besides, we observe that the S-shape in the updated heat capacities is much more pronounced in even-even Dy isotopes than in even-odd ones, whereas the un-updated heat capacities do not clearly exhibit this S-shape. Therefore, the updated heat capacities should provide a more convincing evidence for the signature of pairing phase transition in nuclear systems.

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Deformation dependence of thermal properties of hot rotating 184Re with inclusion of nuclear pairing fluctuations

Kargar,

Afrookhteh

2023

Results in Physics

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Investigation of empirical heat capacity in hot-rotating A ∼ 200 nuclei

Cited by 4 publications

References 34 publications

Systematic investigation on semi-empirical thermodynamic quantities of excited nuclei using canonical ensemble

Systematic investigation on semi-empirical thermodynamic quantities of excited nuclei using canonical ensemble

Updated heat capacities of \(^{161-164}\)Dy nuclei

Deformation dependence of thermal properties of hot rotating 184Re with inclusion of nuclear pairing fluctuations

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