G-FACTORS OF EXCITED-STATES IN TL-205, TL-203 MEASURED BY TRANSIENT FIELD INTERACTION AT HIGH RECOIL VELOCITIES

Following Coulomb excitation with 120 MeV 40Ca and 190 MeV 81Br beams, fast Pt recoils were passed through thin, polarized Fe foils; the observed Larmor precession angles were used to calibrate the transient magnetic field against the known g-factor for the 2+ state in 194Pt. Precession data obtained with the 40Ca beam for the two lowest excited states in Tl isotopes yielded the following g-factors: g(205Tl, 5 2+) = 0.89±0.26; g(205Tl, 3 2+) = 0.01±0.08; g(203Tl, 5 2+) = 1.03±0.43; g(203Tl, 3 2+) = -0.01±0.11. The observed g-factors are much smaller than expected for the equivalent states in the one-proton-hole nucleus 207Tl, underscoring the importance of particle-core coupling effects. © 1979.