An analysis of β-delayed neutron emission of even-even neutron-rich nuclei with proton-neutron QRPA

β-delayed neutron emission probabilities of even-even nuclei are examined with a proton-neutron quasi-particle random-phase-approximation (pnQRPA). To calculate a light particle evaporation from excited states of daughter nucleus populated by β-decay, the Hauser-Feshbach statistical model is used. We discuss effects of isospin T = 0 pairing, tensor force and nuclear deformation on the β-delayed neutron emission probability. We find that the effect of nuclear deformation is essential rather than the that of isospin T = 0 pairing and tensor force to give an appropriate β-feedings to energy window of neutron emission. The obtained β-delayed neutron emission probabilities are in reasonable agreement with the experimental data of several typical delayed neutron emitters. The results are also compared with the FRDM + QRPA calculation. We conclude that the present approach is promising to calculate β-delayed neutron.