Measurement of g-factors in 170Yb, 172Yb and 174Yb by transient field interaction at high recoil velocities

Abstract A beam of 40 Ca ions at 168 MeV has been used to Coulomb excite high-spin states in 169 Tm and 170, 172, 174 Yb which recoiled through thin polarized iron at ν / c ≈ 3.5%. An enhanced transient field ≈ 6 times larger than the Lindhard-Winther prediction was observed and calibrated against the known g -factors in 169 Tm. Individual g -factors could not be extracted because of strong feeding; nevertheless, deviations from rotational behaviour (constant g -factors) would be detectable. Empirical fits to microscopic calculations of the rotational g -factors below spin 12 + suggest that if deviations from the simple rotational formula occur, they should be of the form g ( J ) = g 0 (1 + αJ 2 ). We find the following values in 170, 172, 174 Yb: α × 10 3 = −0.5±1.5, +1.0±1.5. The uncertainties are the level at which deviations from rotational behaviour are expected to occur. The results are discussed in terms of Coriolis anti-pairing effects.