Proton Radioactivity from Highly Deformed Nuclei

Proton radioactivity from ¹⁴¹Ho and ¹³¹Eu has been identified. The ¹⁴¹Ho proton transition has an energy Eₚ0ex0ex=0ex0ex1169(8)keV, a half-life t1/20ex0ex=0ex0ex4.2(4)ms, and is assigned to the decay of the 7/2^-[523] Nilsson state. The ¹³¹Eu transition has an energy Eₚ0ex0ex=0ex0ex950(8)keV and a half-life of 26(6) ms, consistent with decay from either the 3/2⁺[411] or 5/2⁺[413] Nilsson orbital. The proton decay rates deviate significantly from calculations assuming spherical configurations, and thus indicate the onset of large deformations in the region of the proton drip line below Z0ex0ex=0ex0ex69.