Rotation alignment in neutron-rich Cr isotopes: A probe of deformed single-particle levels across N=40

TL;DR

This paper uses the Projected Shell Model to investigate rotation alignment in neutron-rich Cr isotopes near N=40, revealing early alignment at spin 8 and linking irregular moments of inertia to deformed single-particle levels.

Contribution

It demonstrates the occurrence of rotation alignment in neutron-rich Cr isotopes at low spins and connects these phenomena to the underlying deformed single-particle structure.

Findings

Rotation alignment occurs at spin 8 in Cr isotopes.

Aligning particles differ across isotopes due to shell filling.

Irregular moments of inertia indicate deformed single-particle schemes.

Abstract

Recent experiments have reached the neutron-rich Cr isotope with N=40 and confirmed enhanced collectivity near this sub-shell. The current data focus on low-spin spectroscopy only, with little information on the states where high-j particles align their spins with the system rotation. By applying the Projected Shell Model, we show that rotation alignment occurs in neutron-rich even-even Cr nuclei as early as spin 8 and, due to shell filling, the aligning particles differ in different isotopes. It is suggested that observation of irregularities in moments of inertia is a direct probe of the deformed single-particle scheme in this exotic mass region.