We have made the first clear measurements of rotational damping widths in nuclei. In a mixture of three Yb nuclei, these widths are $300\pm 60\mathrm{keV}$ between 1.2 and 1.5 MeV $\gamma$-ray energy $\left[\sim \right(37–57\left)ħ\right]$. Compound damping and motional narrowing are discussed in connection with these results.

• Received 19 October 2001

DOI:https://doi.org/10.1103/PhysRevLett.88.142501