UNEXPECTED PROPERTIES OF THE SCISSORS MODE IN THE ODD-MASS NUCLEUS ER-167

We report a study of the Er-167(gamma,gamma') reaction in the excitati on energy range E(x) = 1.9-4.3 MeV. The total magnetic dipole strength above 2.5 MeV attributed to the scissors mode amounts to B(M1)up arro w = 3.14(1.12) mu(N)(2), much larger than all values previously report ed for odd-A nuclei, but fitting well into the systematics in the rare -earth region. In the region E(x) > 3.9 MeV not accessed in previous e xperiments appreciable M1 strength is found indicating a spreading of the scissors mode over a large energy interval of about 2 MeV. The dat a can be described quantitatively by an interacting boson-fermion mode l calculation using boson g-factors g pi(g nu) = 1(0) mu N.