No abstract

In the present work we perform a systematic shell model study of Gamow-Teller transition strength distributions in sd shell nuclei using ab initio effective interactions. The ab initio effective interactions are based on in-medium similarity renormalization group (IM-SRG) and coupled-cluster effective interaction (CCEI) approaches. The aim of the present work is to test the predictive power of ab initio effective interactions by using the available experimental data of Gamow-Teller strength distributions in sd shell nuclei. We perform calculations for P, 31 P → 31 Si, and 32 S → 32 P transitions. For comparison we also show the results obtained by using the phenomenological USDB Hamiltonian. The phenomenological USDB results of the Gamow-Teller (GT+/GT−) strength distributions show reasonable agreements with the experimental data in comparison to the ab initio interactions. We also calculate the electron capture reaction rates for 23 Na(e − , ν) 23 Ne and 25 Mg(e − , ν) 25 Na using ab initio and USDB interactions.

In the present work, we have reported shell model results for open shell nuclei Ne, Mg and Si isotopes with 10 ≤ N ≤ 20 in sd-shell model space. We have performed calculations in sd shell with two ab initio approaches: in-medium similarity renormalization group (IM-SRG) and coupledcluster (CC) theory. We have also performed calculations with phenomenological USDB interaction and chiral effective field theory based CEFT interaction. The results for rotational spectra and B(E2; 2 + 1 → 0 + 1 ) transitions are reported for even-mass isotopes. The IM-SRG and CC results are in reasonable agreement with the experimental data except at N =20. This demonstrates a validity of ab initio description of deformation for doubly open-shell nuclei for sd shell. To see the importance of pf orbitals, we have also compared our results with SDPF-MU interaction by taking account of 2p − 2h and 4p − 4h configurations in sd-pf -shell model space.

The Tz = − 3 2 nucleus 21 Mg has been studied by Coulomb excitation on 196 Pt and 110 Pd targets. A 205.6(1)-keV γ-ray transition resulting from the Coulomb excitation of the 5 * panu.ruotsalainen@jyu.fi; Present address:

In the present paper, we have done the systematic study of low-lying energy spectrum (positive parity) for oxygen ( 18−23 O) and fluorine ( 18−24 F) chain using ab initio no core shell model. We have used inside nonlocal outside Yukawa (INOY) potential, which is a two body interaction but also have the effect of three body forces by short range and nonlocal character. Also we have performed calculations with N3LO, and N2LOopt interactions and corresponding results are compared with the experimental data and phenomenological interaction USDB. The largest model space we have reached for 18−21 O and 18−19 F is N max =6 and for other oxygen and fluorine isotopes is N max =4.We have also discussed the binding energy for O and F chain. The over binding in ground state (g.s.) energy in neutron rich oxygen isotopes is observed in our largest model space calculations.