Behavior of Intruder Based States in Light Bi and Tl Isotopes: The Study of 187 Bi Alpha Decay

The excitation energies of the single-particle normal and intruder levels in both `83T1 and 187Bi were measured for the first time via the ct decay of 187Bi produced in the 97Mo(92Mo,pn) 187Bi reaction. The previously unobserved 187Bi ground state (kw) to 183T1 ground state (s1/2) a transition was identified establishing the 187Bi intruder state excitation energy to be 112(21) keV, 70 keV less than that of the same level in 189Bi.