Development of large deformation in 62Cr

Area of Science:

• Nuclear Physics
• Atomic and Molecular Physics

Background:

• Neutron-rich nuclei exhibit unique structural properties due to the influence of the nuclear force.
• Understanding collectivity and deformation in isotopes near closed shells is crucial for nuclear structure models.

Purpose of the Study:

• Investigate the nuclear structure of neutron-rich chromium isotopes 60Cr and 62Cr.
• Determine deformation lengths and identify excited states to probe nuclear collectivity.
• Explore the development of large deformation in 62Cr near the N=40 neutron number.

Main Methods:

• Proton inelastic scattering experiments were conducted in inverse kinematics.
• Deformation lengths (δ) were extracted for 60Cr and 62Cr.
• An excited state in 62Cr was identified and its spin-parity assigned.

Main Results:

• Deformation lengths of 1.12(16) fm for 60Cr and 1.36(14) fm for 62Cr were determined.
• Enhanced collectivity was evidenced in both isotopes.
• A new excited state at 1180(10) keV in 62Cr was identified, assigned 4+ spin-parity.
• The Ex(4+)/Ex(2+) ratio indicates rapid development of large deformation in 62Cr near N=40.

Conclusions:

• The results provide evidence for enhanced collectivity in neutron-rich 60Cr and 62Cr.
• The findings in 62Cr suggest the development of significant deformation around the N=40 neutron number.
• The importance of gd-shell admixture in nuclear structure above N=40 is highlighted through comparison with shell model calculations.