Background: The nucleon-nucleus scattering has been studied using Gaussain potential withspin-orbit term of Thomas type to fit the experimental scattering phase shifts (SPS). Recently,Hulthen potential without spin-orbit term has been utilised for studying α–nucleon scattering with phase function method (PFM).Purpose: The main objectives of this paper are:1. To obtain the best possible interaction potentials that best describe the neutron-α elasticSPS in various channels.2. To compute the partial cross-sections for scattering p-states and the total cross-section forthe reaction.Methods: The local interaction potential is modeled using Gaussian function. The non-localspin orbit term is chosen to be proportional to derivative of local potential. The phase function method has been numerically solved using 5th order Runge-Kutta method to compute the SPS. The model parameters are varied in an iterative fashion to minimise the mean absolute percentage error (MAPE) w.r.t. the experimental SPS.Results:1. The SPS for S, P and D channels have been obtained with MAPE values less than 3%.2. The partial cross-sections for p 1/2 and p 3/2 have been plotted and the respective resonance energies and FWHM have been found to be in reasonable agreement with values in literature.3. The total cross-section for the reaction has been determined and found to be matching well with experimental findings.Conclusions: Gaussian potential with associated spin-orbit term has been shown to be areasonably good choice for explaining the n-α scattering reaction.
Background: The isotopes of Rb (Z=37) are one proton away from semi-magic (Z=38) proton number and deficits the characteristic of a spherical nucleus. In the 85,86Rb nuclei, the γ-ray spectroscopy are already performed and given an indication of Magnetic Rotation (MR) which usually observed in nearly spherical nuclei. The angular correlation measurements were used to find the spin and parity of the states.Purpose: To confirm the spin and parity of the states in both the nuclei using Directional Correlation of Oriented (DCO) states ratio and polarization asymmetry (Δ) measurements.Methods: The excited states of the 85,86Rb nuclei were populated via the 76Ge(13C,p3n/p2n) reaction at a beam energy of 45 MeV. The γ-rays emitted from the excited states were detected using Indian National Gamma Array (INGA) spectrometer at the Tata Institute of Fundamental Research (TIFR), Mumbai India.Results: The values of the DCO states ratio and polarization asymmetry (Δ) were obtained and utilized to confirm the spin-parity of the states in the 85,86Rb nuclei. The polarization asymmetry (Δ) values were obtained for the first time using Compton-suppressed clover detectors.Conclusions: In 85Rb, the spin and parity of 3491.1-, 4135.4-, 4757.2- and 5419.3 keV levelsare confirmed and for the 5312.2-, 5611.8 and 6335.9 keV states, only the spin is established. The mul-tipolarity assignment of the 224.3-, 331.5-, 732.8-, 778.1-, 865.4-, 973.5-, 1002.4-,1427.5-, 1453.7-, 1598.2-, 1814.1- and 1881.5 keV γ-ray transitions allowed to confirm the spinand parity of most of the levels above the 6- isomer in 86Rb.
Background: Typically 3He-α reaction has been modeled using Gaussian and Hulthen potentials without incorporating the non-local spin-orbit interaction.Purpose: To obtain the scattering phase shifts (SPS) for α-3He radiative capture reaction for partial waves with total angular momentum J = 1/2, 3/2, 5/2, 7/2 having negative parities and J = 1/2 with positive parity, using Morse potential as the model of interaction along with the associated spin-orbit term.Methods: Phase function method is employed for determining phase shifts in an iterative fashion, by making changes to model parameters, to ensure minimisation of mean absolute percentage error (MAPE) w.r.t. the experimental SPS. Results: SPS have been obtained for 1/2+, 1/2-, 3/2-, 5/2- and 7/2- with MAPE values of 3.2, 1.0, 0.8, 17.6 and 6.5 respectively. The corresponding interaction potentials and partial cross-sections have been plotted. The resonance frequencies for the 5/2- and 7/2- scattering states are closely matching with experimental ones.Conclusions: The interaction potentials for different ℓ-channels of 7Be have been constructed by considering Morse potential and spin-orbit terms by considering experimental scattering phase shifts for 3He-alpha reaction.
The signature splitting and signature inversion in rotational bands belonging to configurations in even-even deformed 132,134,136Ce nuclei have been studied. These Ce isotopes are interesting candidates to probe for signature of triaxiality. The energy staggering index S(I) is found nearly constant for band 4 and 5 132Ce. similarly, S(I) is also found nearly constant as a function of spin 134 Ce. The observed signature splitting in these two nuclei does not support low K (projection on symmetry axis) value for these bands on the other hand, high K value is not expected for and / orbitals at Z=58. Hence, this low and constant signature splitting is only possible due to triaxiality. However, in 136Ce favored and unfavored partner bands (B1 and B2) Shows normal signature splitting and indicate axially symmetric shape for 136Ce.
Background: Nuclear transfer reactions are a useful tool to study the structure of a nucleus. For reactions involving weekly bound nuclei, breakup effects can play significant role and theoretical calculations can be computational expensive in such cases. Purpose: To utilize the Lagrange-mesh and R-matrix methods for nuclear transfer reactions. Methods: We use the adiabatic distorted wave approximation (ADWA) method which can approximately treats the breakup effects in a simpler manner. In our approach, we apply the R-matrix method combining it with the Lagrange-mesh method, which is known to provide the fast and accurate computations. Results: As a test case, we calculate the angular distribution of the cross sections for the 56Fe(d, p)57Fe reaction, where deuteron breakup effects play important role. Conclusions: We show that these methods work well in the ADWA framework, and we look forward to applying these methods in coupled channel calculations.
