Abstract

This article presents a compact theoretical and computational study of the structure and beta-delayed neutron emission of the neutron-rich nucleus 9Li. A connected framework was used, combining an effective shell-model benchmark for low-lying spectroscopy and Gamow-Teller feeding, a two-body 8Li+n description of the bound structure, a halo or core-EFT-style fit to the near-threshold sector, and a daughter-state decay map for 9Be leading to neutron emission. The bound-state sector reproduced the dominant low-energy observables, including a ground-state neutron binding energy near -4.06 MeV and a first excited-state gap near 2.69 MeV. The fitted EFT-style sector gave Ep3/2=-4.059659 MeV and ΔE=2.690697 MeV, while also predicting a larger rms radius for the less bound excited configuration. The shell-model benchmark supplied the principal 3/2-, 5/2-, and 1/2- branches together with effective B(GT) strengths used in the decay calculation. The delayed-neutron spectrum reproduced the dominant low-energy neutron peak at about 0.68 MeV and the adopted total delayed-neutron probability Pn=0.508. A daughter-state decay map showed that neutron emission is controlled mainly by the lowest unbound fed states in 9Be, especially the 5/2- state at Ex=2.430 MeV, while higher states populate the upperenergy tail. The continuum analysis also showed that detailed resonance extraction remains numerically delicate, so the strongest conclusions of the present work concern bound-state observables, feeding structure, daughter-state interpretation, and spectrum-level decay quantities. The study therefore provides a compact phenomenological baseline that helps bridge the gap between experimental observables and theoretical description in neutronrich exotic nuclei.

Keywords

Exotic nuclei, Lithium-9, beta-delayed neutron emission, daughter-state feeding, halo effective field theory