Observation of Rotational Band in the Odd-Z Transfermium Nucleus 251/101Md

A rotational band has been unambiguously observed in an odd-proton transfermium nucleus for the first time. An in-beam {gamma}-ray spectroscopic study of {sub 101}{sup 251}Md has been performed using the {gamma}-ray array JUROGAM combined with the gas-filled separator RITU and the focal plane device GREAT. The experimental results, compared to Hartree-Fock-Bogolyubov calculations, lead to the interpretation that the rotational band is built on the [521]1/2{sup -} Nilsson state.