Atomic-Beam Measurement of the Hyperfine Structure and Nuclear Moments of Iodine-131

The nuclear magnetic dipole and nuclear electric quadrupole interaction constants a and b have been measured in 8-day iodine-131 by an atomic beam magnetic resonance experiment. The results are a=575.903±0.007 Mc/sec, b=578.866±0.075 Mc/sec. The zero-field hyperfine splittings computed from these values of a and b are Δν(5, 4)=3292.99±0.09 Mc/sec, Δν(4, 3)=2138.22±0.05 Mc/sec, Δν(3, 2)=1314.24±0.07 Mc/sec. The nuclear magnetic dipole moment and nuclear electric quadrupole moment are calculated as μ₁₃₁=2.738±0.001 nm, Q₁₃₁=-0.41±0.01×10^-24 cm². The value of μ₁₃₁ obtained here differs slightly from that obtained by other workers, while the value of Q confirms an earlier measurement made by a different method.