The Electric Quadrupole Moments ofGa69andGa71An Atomic Beam Study of the Hyperfine Structures of theP122andP322States ofGa69andGa71

An investigation of the hyperfine structures of the ground ${}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}$ state, and the metastable ${}_{}{}^2{}_{}{}^{}P_{\frac{3}{2}}^{}{}_{}{}^{}$ state of the two isotopes 69 and 71 of gallium has been made with the zero-moment method of atomic beams. Six zero-moment peaks, three for each isotope, of the metastable state and two, one for each isotope, of the ground state have been observed. It has been found that the h.f.s. energy levels for the higher state can be described by an equation of the form $E=\frac{\mathrm{aC}}{2}+bC(C+1\mathrm{})\mathrm{}$, where "$a$" and "$b$" are the interval rule and quadrupole interaction constants, respectively. $\{{\mathrm{Ga}}^{69}: \frac{b}{a}=0.0136\mathrm{}\pm 0.0004,{\mathrm{Ga}}^{71}: \frac{b}{a}=0.0068\mathrm{}\pm 0.0004\}\{b=(8.69\mathrm{}\pm 0.43)\times {10}^{-5\mathrm{}} {\mathrm{cm}}^{-1\mathrm{}},b=(5.51\mathrm{}\pm 0.39)\times {10}^{-5\mathrm{}} {\mathrm{cm}}^{-1\mathrm{}}\}\{a=(6.39\mathrm{}\pm 0.12)\times {10}^{-3\mathrm{}} {\mathrm{cm}}^{-1\mathrm{}},a=(8.11\mathrm{}\pm 0.11)\times {10}^{-3\mathrm{}} {\mathrm{cm}}^{-1\mathrm{}}.\}$ From these the h.f.s. separations are ${\mathrm{Ga}}^{69}: \Delta \nu =(0.0362\mathrm{}\pm 0.0007) {\mathrm{cm}}^{-1\mathrm{}}; {\mathrm{Ga}}^{71}: \Delta \nu =(0.0474\mathrm{}\pm 0.0007) {\mathrm{cm}}^{-1\mathrm{}}$ and the quadrupole moments are $Q^{69}=0.20\mathrm{}\times {10}^{-24\mathrm{}} {\mathrm{cm}}^2; Q^{71}=0.13\mathrm{}\times {10}^{-24\mathrm{}} {\mathrm{cm}}^2.$ The nuclear spins are verified to be $\frac{3}{2}$. From the zero-moment peaks of the normal state we obtain