Sn Nuclei Research Articles

A study of tin electrodeposition from ethaline: The electrode material effect

AbstractThis article studies the influence of electrode material on tin (Sn) electrodeposition from deep eutectic solvent. The Sn electrodeposition from ethaline‐based electrolyte onto glassy carbon (GC) and Pt substrates has been studied using cyclic voltammetry and chronoamperometry. The patterns and parameters of Sn nucleation and growth processes have been determined by means of Scharifker and Hills and Scharifker–Mostany models. Results show that Sn nucleation onto GCE follows instantaneous 3D nucleation, while in the case of PtE, it is controlled by adsorption, instantaneous 3D nucleation, and residual water reduction. The growth mechanism is diffusion‐controlled for both electrodes. The parameters of Sn electrodeposition onto GCE and PtE such as diffusion coefficient (D), nucleation rate (A), and active site density of Sn nuclei (No) are evaluated. The results showed that A and No increase linearly as the deposition potential is displaced towards more electronegative values while D is almost unchanged, regardless of the involved working electrode. The morphology and the structure of the electrodeposited Sn are also discussed based on scanning electron microscopy, X‐ray diffraction, and energy‐dispersive X‐ray spectroscopy investigations.

Sn nucleation and growth from Sn(II) dissolved in ethylene glycol: Electrochemical behavior and temperature effect

Thermodynamic and kinetic aspects of Sn nucleation and growth processes onto a glassy carbon electrode from SnCl2·2H2O dissolved in ethylene glycol solutions were studied. Typical reduction and oxidation peaks observed in voltammograms have demonstrated the capability of ethylene glycol solutions to electrodeposit Sn. The temperature-dependence of diffusion coefficient values derived from potentiodynamic and potentiostatic studies helped to determine and validate estimations of the activation energy for Sn(II) bulk diffusion. Chronoamperometric results have identified that, the suitable model to describe the early stage of Sn electrodeposition could be composed of Sn three-dimensional nucleation and diffusion-controlled growth and water reduction contributions, which was duly validated by theoretical and experimental approaches. From the model, typical kinetic parameters such as the nucleation frequency of Sn (A), number density of Sn nuclei (N0), and diffusion coefficient of Sn(II) ions (D), were determined. The presence of Sn nuclei with excellent quality and their structures were verified using SEM, EDX, and XRD techniques.

Proton and neutron density distributions at supranormal density in low- and medium-energy heavy-ion collisions. II. Central Pb + Pb collisions

This paper represents a continuation of our investigation into the limitations on total, proton, and neutron particle number densities, as well as the asymmetry of proton and neutron density distributions achievable in central heavy-ion collisions. We explore these aspects at low and medium energies within the framework of the Boltzmann-Uhlenbeck-Uehling (pBUU) transport and time-dependent Hartree-Fock (TDHF) models. Previous studies, focusing on symmetric and asymmetric collisions of Ca and Sn nuclei [1], and initial results on Pb-nuclei collisions [2], emphasized the role of the Coulomb interaction in these events. Our findings indicated that: (i) the highest total densities predicted at Ebeam=800 MeV/nucleon were on the order of ≈2.5ρ0 (ρ0=0.16fm−3), (ii) the proton-neutron asymmetry for maximal densities, δ=(ρnmax−ρpmax)/(ρnmax+ρpmax), did not generally exceed the asymmetry in the initial state of the collision at all beam energies and tended to decrease during the reaction, and (iii) a significant portion of this asymmetry had its microscopic origin in Coulomb forces, masking the pure nuclear contribution. These new findings, particularly relevant in the astrophysical context, are further examined in this work, focusing on the heaviest target-projectile combination Pb212,208 accessible in an experiment. We introduce the SkT3 Skyrme force model, not previously used for the Pb system, and compare it to the SV-bas and SV-sym34 models to explore the symmetry-energy dependence of the results. Contour plots of nucleonic densities are presented, contrasting the time evolution of the density distributions in low (TDHF) and high (pBUU) models. We also present the evolution of normalized maximal proton, neutron, and total nucleon number density with increasing beam energy in the full pBUU model and the Vlasov approximation, aiming to explore the impact of correlations in the reaction. The time evolution of the proton and neutron density distributions in the plane transverse to the beam direction is illustrated at both low and high beam energy. In conclusion, our detailed examination of the Pb system in this work provides further essential evidence that the aforementioned findings (i)–(iii) are only weakly dependent on system size and a symmetry-energy model, and thus, they are of more general importance. Published by the American Physical Society 2024

Shell-Driven Localized Oxide Nanoparticles Determine the Thermal Stability of Microencapsulated Phase Change Material.

Not all encapsulation techniques are universally apt for every type of phase change material (PCM), highlighting the imperative for methodological precision. This study addresses the challenges of microencapsulated PCM (MEPCM) arising from the immiscible pairing of α-Al2O3 nanoparticles with Sn microparticles. The high-speed impact blending (HIB) dry synthesis technique is employed, facilitating large-volume production of Sn@α-Al2O3 MEPCMs. The resulting MEPCMs not only seamlessly endure 100 cycles of melting-solidification but also, with the strategic incorporation of a glass frit, exhibit remarkable thermal durability, withstanding up to 1000 melting-solidification cycles. Even under ultrafast thermal fluctuations, the α-Al2O3 shell remained resilient through 100 cycles. A marked reduction in supercooling is observed, which is attributed to the formation of SnO and SnO2 nanoparticles within the α-Al2O3 crystal lattice. The atomically resolved interface dynamics between SnO2 and α-Al2O3 play a pivotal role, lowering the energy barrier for Sn nuclei formation during solidification. This affects the accelerated Sn nucleation rate, effectively suppressing supercooling. Such insights offer a deeper understanding of the interplay between nanoscale crystal lattice imperfections and their implications for energy storage applications.

Bayesian model averaging for nuclear symmetry energy from effective proton-neutron chemical potential difference of neutron-rich nuclei

The data-driven Bayesian model averaging is a rigorous statistical approach to combining multiple models for a unified prediction. Compared with the individual model, it provides more reliable information, especially for problems involving apparent model dependence. In this work, within both the non-relativistic Skyrme energy density functional and the nonlinear relativistic mean field model, the effective proton-neutron chemical potential difference Δμpn⁎ of neutron-rich nuclei is found to be strongly sensitive to the symmetry energy Esym(ρ) around 2ρ0/3, with ρ0 being the nuclear saturation density. Given discrepancies on the Δμpn⁎-Esym(2ρ0/3) correlations between the two models, we carried out a Bayesian model averaging analysis based on Gaussian process emulators to extract the symmetry energy around 2ρ0/3 from the measured Δμpn⁎ of 5 doubly magic nuclei 48Ca, 68Ni, 88Sr, 132Sn and 208Pb. Specifically, the Esym(2ρ0/3) is inferred to be Esym(2ρ0/3)=25.6−1.3+1.4MeV at 1σ confidence level. The obtained constraints on the Esym(ρ) around 2ρ0/3 agree well with microscopic predictions and results from other isovector indicators.

Designing strong and stiff HCP and BCC Mg alloy structures by templating hard faceted phase using Sn and RE elements

Compared to alternative materials (aluminum alloys and steel), magnesium alloys have low strength and modulus which restricts further applications in critical structural components. To overcome this limitation, we have successfully designed a strong and stiff magnesium-lithium alloy (LAZWMGT) by using Sn and RE (Gd, Y) nuclei to refine HCP α-Mg grains and forming secondary Mg2Sn inside primary Mg grains. Although the bulk Gibbs free energy favors the dissolution of HCP α-Mg and growth of BCC β-Li grains, the dispersion of thermally stable Mg2Sn, Al2Gd, and Al2Y particles inside the BCC β-Li grains can actually template the nucleation of HCP α-Mg heterogeneously. Because the Mg2Sn, Al2Gd, and Al2Y phases are hard (E > 76 GPa) and have an entropy of melting greater than 16.6 J/mol·K, they are faceted crystals and semi-coherency exists between the HCP α-Mg and Mg2Sn, Al2Gd, and Al2Y particles, leading to limited growth orientations at slow rate. As a result, new HCP α-Mg grains inside BCC β-Li do not coarsen. Therefore, both strength and stiffness are increased significantly up to YS: 319 MPa, UTS: 365 MPa, and E: 64.5 GPa. To quantify each phase's contribution to Young's modulus, nanoindentation has been used to measure the stiff particles as well as the soft BCC β-Li. It has been found by XPS experiments and DFT calculations that strong covalent Mg-Mg and Mg-X bonds in BCC β-Li enhances when Sn or RE presents either in solution heat treatment or as Mg2Sn precipitates, justifying the rigidity and directionality bonds as a result of Sn and RE. In addition, the effects of Sn and RE on grain boundary, solid solution, and precipitation strengthening have been predicted.

Low-energy quadrupole collectivity of Sn nuclei in self-consistent calculations with a semi-realistic interaction

Low-energy quadrupole collectivity of Sn nuclei in self-consistent calculations with a semi-realistic interaction

Isotopic dependence of (n,α) reaction cross sections for Fe and Sn nuclei

The (n,α) reactions play an important role for the energy generation and the synthesis of chemical elements in the stars, as well as for nuclear engineering and medical applications. The aim of this study is to explore the evolution of (n,α) reactions in Fe and Sn isotope chains in order to assess the cross section properties with the increase of neutron number in target nucleus, and to make a comparison with other relevant neutron induced reactions. The cross section calculations are based on the statistical Hauser-Feshbach and exciton models in TALYS nuclear reaction code, using global optical model potential that is additionally adjusted by the (n,α) cross section data for 54Fe and 118Sn. The calculations of (n,α) reactions in Fe and Sn isotopes provide the insight into their isotopic dependence and properties over the complete relevant range of neutron energies. The cross sections result in pronounced maxima at lower-mass isotopes, and rather strong decrease for neutron-rich nuclei consistent with the reduction of the reaction Q-value and increased contributions from other exit channels from compound nucleus. The analysis of the Maxwellian averaged cross sections at temperatures in stellar environment shows that the (n,α) reactions have significant contributions for low-mass Fe isotopes, that is opposite than for Sn isotopes. For both neutron rich isotopes γ and neutron emissions dominate, with their interplay depending on the temperature involved.

An alternative viewpoint on the nuclear structure towards 100Sn: Lifetime measurements in 105Sn

This work aims at presenting an alternative approach to the long standing problem of the B(E2) values in Sn isotopes in the vicinity of the N=Z double-magic nucleus 100Sn, until now predominantly measured with relativistic and intermediate-energy Coulomb excitation reactions. The direct measurement of the lifetime of low-lying excited states in odd-even Sn isotopes provides a new and precise guidance for the theoretical description of the nuclear structure in this region. Lifetime measurements have been performed in 105Sn for the first time with the coincidence Recoil Distance Doppler Shift technique. The lifetime results for the 7/21+ first excited state and the 11/21+ state, 2+(104Sn) ⊗ν1g7/2 multiplet member, are discussed in comparison with state-of-the-art shell model and mean field calculations, highlighting the crucial contribution of proton excitation across the core of 100Sn. The reduced transition probability B(E2) of the 11/21+ core-coupled state points out an enhanced staggering with respect to the B(E2; 21+→01+) in the even-mass 104Sn and 106Sn isotopes.

Anomaly-Induced Quenching of gA in Nuclear Matter and Impact on Search for Neutrinoless ββ Decay

How to disentangle the possible genuine quenching of gA caused by scale anomaly of QCD parameterized by the scale-symmetry-breaking quenching factor qssb from nuclear correlation effects is described. This is accomplished by matching the Fermi-liquid fixed point theory to the “Extreme Single Particle (shell) Model” (acronym ESPM) in superallowed Gamow–Teller transitions in heavy doubly-magic shell nuclei. The recently experimentally observed indication for (1−qssb)≠0—that one might identify as “fundamental quenching (FQ)”—in certain experiments seems to be alarmingly significant. I present arguments for how symmetries hidden in the matter-free vacuum can emerge and suppress such FQ in strong nuclear correlations. How to confirm or refute this observation is discussed in terms of the superallowed Gamow–Teller transition in the doubly-magic nucleus 100Sn and in the spectral shape in the multifold forbidden β decay of 115In.

Nuclear Spin-Isospin Response within the Fayans Functional

An effective approximation to a fully self-consistent global description of the total force function of b decay within the framework of the theory of finite Fermi systems is presented, based on the calculation of ground states within the framework of the modified energy density functional of Fayans et al. (DF3-f) and the continuum quasiparticle random phase approximation (CQRPA). The isovector parameter ℎ2− of the volume part of the functional has been refined, the permissible range of which was determined earlier by us from restrictions on the parameters of the equation of state for nuclear matter—the symmetry energy and its derivative at equilibrium density, obtained from a joint analysis of the value of the ‘‘neutron skin’’ ΔRnp of the nuclei 208Pb and 48Ca, found in the PREX-II and CREX experiments, results of ab initio calculations of the properties of the ground states of nuclei with the interaction of N3LO and systematics of data on the masses of neutron stars from astrophysical observations. New calculations of the Gamow–Teller strength functions for the reference doubly magic nuclei 208Pb and 132Sn, as well as for the nucleus 130Sn with developed neutron pairing have been carried out. In the proposed model, the global DF3-a + CQRPA calculations of beta-decay half-lives of heavy (quasi)spherical nuclei with Z = 81–83 and T1/2 240 s are conducted. Experimental lifetimes are described with accuracy up to factor 5.

Angular momentum of doubly magic 132Sn fission product: Experimental and theoretical aspects

Despite the numerous theoretical and experimental works published very recently, the way in which fission fragments acquire their angular momentum is still an open question. This angular momentum generation mechanism is important not only for improving our understanding of the fission process, but also for nuclear energy applications, since the angular momentum of fission fragments strongly impact the prompt gamma spectra and consequently the decay heat in a reactor. In this context, within the framework of a collaboration between the ‘Laboratoire de Physique Subatomique et Corpusculaire’ (LPSC, France), the ‘Institut Laue Langevin’ (ILL, France) and the CEA-Cadarache (France), an experimental program was developed on the LO-HENGRIN mass-spectrometer with the aim of measuring isomeric ratio of some fission products for different thermal-neutron-induced fission reactions. This paper will be focused on the results obtained for the spherical nucleus 132Sn following thermal-neutron-induced fission of both 235U and 241Pu targets. To further challenge the angular momentum generation models, 132Sn isomeric ratio (IR) was measured as a function of 132Sn fission product kinetic energy (KE). The angular momentum was determined by combining our experimental data with the calculations performed with the FIFRELIN Monte Carlo code. A clear angular momentum decrease with KE was observed for both reactions. Lastly, we investigate the dependence of the 132Sn angular momentum with the incident neutron energy, from thermal region up to 5 MeV (below the second-chance fission). For that, the four free available parameters in FIFRELIN are selected in order to reproduce the average prompt neutron multiplicity. In this way, the angular momentum is deduced for each neutron energy. These results are discussed in terms of the impact of the available intrinsic excitation energy at scission on the spin generation mechanism.

119Sn Mössbauer and magnetization studies of the Heusler alloy Ni2Mn1.48Sn0.52

The results of experimental investigations of the crystal structure, magnetization and Mössbauer spectroscopy of the Heusler alloy Ni2Mn1.48Sn0.52 are reported. The alloy undergoes the martensitic transition from the L21-type cubic structure into 4O-type orthorhombic structure with a thermal hysteresis of ∼23 K. The martensitic transition temperature TM is 309 K. The Curie temperature in the austenitic phase TCA of Ni2Mn1.48Sn0.52 is found to be 316 K. The Mössbauer spectra from the high temperature paramagnetic state at 330 K and the martensitic state at 283 K were both singlets, showing a typical paramagnetic feature in the narrow temperature range just below TM. With further decrease of temperature, the ferromagnetic ordered state also appears in the martensitic phase. The Curie temperature in the martensitic phase TCM is found to be 256 K. Furthermore, the exchange bias effect is observed in the temperature range 1.8 K ≤ T ≤ TB (∼130 K), where TB is an exchange bias blocking temperature. The values of a hyperfine magnetic field at Sn nuclei of Ni2Mn1.48Sn0.52 fall significantly below the molecular magnetic field approximation for S = 1. On the basis of the experimental results, the electronic and magnetic properties of Ni2Mn1.48Sn0.52 are discussed.

Magnetic properties of ferromagnetic Heusler alloy Co2ZrSn

The results of experimental investigations of the crystal structure, permeability, magnetization and Mössbauer spectroscopy of Co2ZrSn are reported. The sample, which was prepared by arc melting, comprised of a Heusler structure Co2ZrSn that coexisted with a small amount of an impurity phase. The Curie temperature TC of Co2ZrSn was found to be 452.3 K. At 1.8 K the magnetic moment of Co2ZrSn was estimated to be 2.0 μB/f.u., confirming that the magnetic moment of Co2ZrSn obeys the Slater-Pauling rule. The temperature variation of the spontaneous magnetization Ms roughly follows the Brillouin function for spin value S = 1/2. However, in the temperature region of T/TC > 0.6, Ms is distinctly higher than the Brillouin function. The TC of Co2ZrSn was almost independent of pressure. The Mössbauer spectroscopy measurements showed that the isomer shift I.S. (1.5 mm/s at 295 K) was approximately temperature independent. At 95 K the value of the hyperfine magnetic field HhfSn at the Sn nuclei was found to be 101 kOe. The temperature variation of HhfSn of Co2ZrSn roughly followed the Brillouin function for S = 1/2. On the basis of the experimental results, the electronic and magnetic properties of Co2ZrSn are discussed.

Neutron transfer reactions on the ground state and isomeric state of a Sn130 beam

The structure of nuclei around the neutron-rich nucleus 132Sn is of particular interest due to the vicinity of the Z = 50 and N = 82 shell closures and the r-process nucleosynthetic path. Four states in 131Sn with a strong single-particle-like component have previously been studied via the (d,p) reaction, with limited excitation energy resolution. The 130Sn(9Be,8Be)131Sn and 130Sn(13C,12C)131Sn single-neutron transfer reactions were performed in inverse kinematics at the Holifield Radioactive Ion Beam Facility using particle-gamma coincidence spectroscopy. The uncertainties in the energies of the single-particle-like states have been reduced by more than an order of magnitude using the energies of gamma rays. The previous tentative Jpi values have been confirmed. Decays from high-spin states in 131Sn have been observed following transfer on the isomeric component of the 130Sn beam. The improved energies and confirmed spin-parities of the p-wave states important to the r-process lead to direct-semidirect cross-sections for neutron capture on the ground state of 130Sn at 30 keV that are in agreement with previous analyses. A similar assessment of the impact of neutron-transfer on the isomer would require significant nuclear structure and reaction theory input. There are few measurements of transfer reaction on isomers, and this is the first on an isomer in the 132Sn region.

New study of the neutron rich 136Te isotope through decay spectroscopy

136Sb is a neutron rich nucleus with one valence proton and three valence neutrons outside the doubly-magic nucleus 132Sn. It plays an important role in the rapid neutron capture process (r-process) as participates in its path further connected to the nucleosynthesis and the type II supernovae. In this work, a new β decay γ ray data on 136Te is obtained. The experiment is performed at the Institute Laue-Langevin using the Lohengrin spectrometer and the thermal neutron-induced fission reaction on $_{92}^{235}{{\rm{U}}_{143}}$. A specific β-β condition method is investigated for the γ-ray detection.

Nuclear symmetry energy components and their ratio: A new approach within the coherent density fluctuation model

A different alternative approach to calculate the ratio of the surface to volume components of the nuclear symmetry energy is proposed in the framework of the coherent density fluctuation model (CDFM). An alternate expression (scheme II) for the ratio is derived consistently within the model. This expression appears in a form more direct and physically motivated than the expression (scheme I) that was used in our previous works within the CDFM and avoids preliminary assumptions and mathematical ambiguities in scheme I. The calculations are based on the Skyrme and Brueckner energy-density functionals for nuclear matter and on the nonrelativistic Brueckner-Hartree-Fock method with realistic Bonn B and Bonn CD nucleon-nucleon potentials. The approach is applied to isotopic chains of Ni, Sn, and Pb nuclei using nuclear densities obtained in self-consistent Hartree-Fock$+\mathrm{BCS}$ calculations with the SLy4 Skyrme effective interaction. The applicability of both schemes within the CDFM is demonstrated by a comparison of the results with the available empirical data and with results of other theoretical studies of the considered quantities. Although in some instances the results obtained for the studied ratio and the symmetry energy components are rather close in both schemes, the proposed scheme II leads to more realistic values that agree better with the empirical data and exhibits conceptual and operational advantages.

Evidence of a sudden increase in the nuclear size of proton-rich silver-96

Understanding the evolution of the nuclear charge radius is one of the long-standing challenges for nuclear theory. Recently, density functional theory calculations utilizing Fayans functionals have successfully reproduced the charge radii of a variety of exotic isotopes. However, difficulties in the isotope production have hindered testing these models in the immediate region of the nuclear chart below the heaviest self-conjugate doubly-magic nucleus 100Sn, where the near-equal number of protons (Z) and neutrons (N) lead to enhanced neutron-proton pairing. Here, we present an optical excursion into this region by crossing the N = 50 magic neutron number in the silver isotopic chain with the measurement of the charge radius of 96Ag (N = 49). The results provide a challenge for nuclear theory: calculations are unable to reproduce the pronounced discontinuity in the charge radii as one moves below N = 50. The technical advancements in this work open the N = Z region below 100Sn for further optical studies, which will lead to more comprehensive input for nuclear theory development.

The kinks in charge radii across N = 82 and 126 revisited

We revisit the studies of the isotopic shift in the charge radii of even–even isotopes of Sn and Pb nuclei at N = 82, and 126, respectively, within the relativistic mean-field (RMF) and relativistic-Hartree–Bogoliubov (RHB) approach. The shell model is also used to estimate isotopic shift in these nuclei, for the first time, to the best of our knowledge. The ground state single-particle energies (SPEs) are calculated for non-linear NL3 and NL3* and density-dependent DD-ME2 parameter sets compared with the experimental data, wherever available. We establish a correlation between the filling of single-particle levels and the isotopic shift in occupation probabilities. The obtained SPE from the RMF and RHB approaches are in line with those used in the shell model and experimental data for both the Sn and Pb isotopic chains. The shell model calculated isotopic shift agrees with RMF and RHB approaches that explain the experimental data quite well in case the of Pb nuclei beyond N=126.

Ternary Fission Mass Distributions of Superheavy Nuclei Within a Statistical Model

Theoretical models predict the existence of an island of stability at the proton shell closures Z = 114 or 120 or 126 and at the neutron shell closure N = 184 due to the microscopic shell effects. In this article, mass distributions of fragments from ternary fission of superheavy nuclei are investigated with the aid of the statistical theory. We have computed the fission mass distributions for the simultaneous decay into three fragments of nuclei 298Fl, $^{304}_{120}$ X and $^{310}_{126} $ X, at the two excitation energies E∗ = 20 and 50 MeV, with the constraint on one of the fragment to be 50Ca and 72Ni. With the fixed third fragments of mass number A3 = 50, 72, asymmetric breakup (A1 ≠ A2) has a larger ternary fission yield for Z = 114, 120 and 126 isotopes. Predominantly, one of the fragments with the neutron closed-shell nucleus (N ≈ 82, 50) is favoured at higher excitation energies. Subsequently, we have considered the ternary fragmentation of the neutron-rich superheavy elements $^{314}_{120}$ X and $^{320}_{126} $ X again for the same excitation energies and fixed third fragment. Interestingly, for the superheavy nucleus $^{314}_{120}$ X, symmetric fission (A1 ≈ A2) with doubly closed-shell nuclei 132Sn for the third fragment 50Ca is favoured at higher E∗. For the isotope $^{320}_{126} $ X, relative yields of fragments with closed shell increase at higher excitation energy.