Measurements on the isotope shift and optical hyperfine structure have been extended to the neutron-deficient mercury isotopes 193, ${193}^m$, and 192. The shifts are -275±15, -251±8, and -284±5 mK, respectively, referred to the isotope 196 as 0. An explanation of these shifts is given in terms of nuclear deformations. The spins of 193 and ${193}^m$ are $\frac{3}{2}$ and 13/2, as given earlier in preliminary reports. The quadrupole moment of 193 is calculated to be -2.0±1.0 b.

• Received 27 December 1965

DOI:https://doi.org/10.1103/PhysRev.147.861