Hyperfine Structure and Nuclear Moments ofBr80andBr80m

The hyperfine-structure-interaction constants have been measured in the ground states of 18-min ${\mathrm{Br}}^{80}$ and 4.5-h ${\mathrm{Br}}^{80m}$. The method used was that of atomic-beam radio-frequency spectroscopy with radioactive detection. The results are: $\left|a\right({\mathrm{Br}}^{80}\left)\right|=323.9\left(4\mathrm{}\right)\mathrm{}$ Mc/sec, $\left|b\right({\mathrm{Br}}^{80}\left)\right|=227.62\left(10\mathrm{}\right)\mathrm{}$ Mc/sec with $\frac{a}{b}<0\mathrm{}$; and $a\left({\mathrm{Br}}^{80m}\right)=166.05\mathrm{}\left(2\right)\mathrm{}$ Mc/sec and $b\left({\mathrm{Br}}^{80m}\right)=-874.9\mathrm{}\left(2\right)\mathrm{}$ Mc/sec. The magnetic-dipole and electric-quadrupole moments of these isotopes were calculated from the measured interaction constants and known nuclear data for the stable Br isotopes; these moments are: $\left|{\mu }_I\right({\mathrm{Br}}^{80}\left)\right|=0.5138\left(6\mathrm{}\right)\mathrm{}$ nm, $\left|Q\right({\mathrm{Br}}^{80}\left)\right|=0.199\left(8\mathrm{}\right)\mathrm{}$ b, $\frac{Q}{{\mu }_I}>0\mathrm{}$; ${\mu }_I\left({\mathrm{Br}}^{80m}\right)=1.3170\mathrm{}\left(6\right)\mathrm{}$ nm, $Q\left({\mathrm{Br}}^{80m}\right)=0.76\mathrm{}\left(3\right)\mathrm{}$ b. The ${\mu }_I\text{'}\mathrm{s}$ are corrected for diamagnetic shielding and the $Q\text{'}\mathrm{s}$ are corrected for core polarization effects.