The hfs of the $\mathrm{}\left(4s4p\right)\mathrm{}{}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$ state of 245-day ${\mathrm{Zn}}^{65}$ and of ${\mathrm{Zn}}^{67}$ has been determined by the optical double-resonance technique. The nuclear spin $I$, and the hfs splittings are: ${\mathrm{Zn}}^{65}$: $I=\frac{5}{2}$, $\nu (\frac{7}{2}-\frac{5}{2})=1875.475\mathrm{}\left(6\right)\mathrm{}$ Mc/sec, $\nu (\frac{5}{2}-\frac{3}{2})=1334.123\mathrm{}\left(6\right)\mathrm{}$ Mc/sec; ${\mathrm{Zn}}^{67}$: $\nu (\frac{7}{2}-\frac{5}{2})=2111.300\mathrm{}\left(3\right)\mathrm{}$ Mc/sec, $\nu (\frac{5}{2}-\frac{3}{2})=1551.565\mathrm{}\left(4\right)\mathrm{}$ Mc/sec. The hfs coupling constants, corrected to second order for interaction with the ${}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}$ and ${}_{}{}^3{}_{}{}^{}P_0^{}{}_{}{}^{}$ states, are: ${\mathrm{Zn}}^{65}$: $A\left(65\right)=+535.163\mathrm{}\left(2\right)\mathrm{}$ Mc/sec, $B\left(65\right)=+2.870\mathrm{}\left(5\right)\mathrm{}$ Mc/sec; ${\mathrm{Zn}}^{67}$: $A\left(67\right)=+609.086\mathrm{}\left(2\right)\mathrm{}$ Mc/sec, $B\left(67\right)=-18.782\mathrm{}\left(8\right)\mathrm{}$ Mc/sec. If quadrupole shielding effects are neglected, the corresponding moments of ${\mathrm{Zn}}^{65}$ are: $\mu \mathrm{}\left(65\right)=+0.7692\mathrm{}\left(2\right)\mathrm{}$ ${\mathrm{\mu }}_{\mathit{N}}$ and $Q\left(65\right)=-0.024\mathrm{}\left(2\right)\mathrm{}\mathrm{b}$. The value given for $\mu \mathrm{}\left(65\right)\mathrm{}$ includes an estimated correction of 0.09(8)% for the hfs anomaly. The ratio of the ${\mathrm{Zn}}^{65}$ and ${\mathrm{Zn}}^{67}$ quadrupole moments is $\frac{Q\left(65\right)\mathrm{}}{Q\left(67\right)\mathrm{}}=-0.1528\mathrm{}\left(3\right)\mathrm{}$; this result is independent of the shielding corrections. The ${\mathrm{Zn}}^{65}$ spin and magnetic moment are consistent with a ${\left(2\mathrm{}{p}_{\frac{3}{2}}\right)}^4{\left(1\mathrm{}{f}_{\frac{5}{2}}\right)}^3$ neutron assignment with some configuration mixing. The small quadrupole moment is compatible with the zero moment expected for a half-filled $f$ shell. In the course of this work, the lifetime of the $\mathrm{}\left(4s4p\right)\mathrm{}{}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$ state of zinc was redetermined and found to be $\tau \left({}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}\right)=20\mathrm{}\left(2\right)\mathrm{}$ μsec. This result includes a large correction for the effects of wall collisions. The theory of wall broadening of optical double-resonance lines is developed.

• Received 14 November 1963

DOI:https://doi.org/10.1103/PhysRev.134.A47