Hyperfine Structure of the $v=0\mathrm{}$, $J=1\mathrm{}$ State in ${\mathrm{Rb}}^{85}$F, ${\mathrm{Rb}}^{87}$F, ${\mathrm{K}}^{39}$F, and ${\mathrm{K}}^{41}$F by the Molecular-Beam Electric-Resonance Method

The electric and magnetic interactions which determine the hfs of the v=0, $J=1\mathrm{}$ state in ${\mathrm{Rb}}^{85}$F, ${\mathrm{Rb}}^{87}$F, ${\mathrm{K}}^{39}$F, and ${\mathrm{K}}^{41}$F have been obtained from spectra measured in zero magnetic field and near zero electric field. A molecular-beam electric-resonance apparatus with two-wire-type focusing fields and a single 30-cm transition field was used. For ${\mathrm{Rb}}^{85}$F and ${\mathrm{Rb}}^{87}$F the electric quadrupole interaction constants are $\frac{\left(e{q}_1{Q}_1\right)}{h}=(-70.3405\mathrm{}\pm 0.0004)$ Mc/sec and $\frac{\left(e{q}_1{Q}_1\right)}{h}=-(34.0313\mathrm{}\pm 0.0010)$ Mc/sec, respectively. Hence the ratio of the Rb nuclear quadrupole moments is $\frac{Q_{85}}{Q_{87}}=+(2.06694\mathrm{}\pm 0.00006)$. Comparison with data on the electric quadrupole interaction constants for ${\mathrm{Rb}}^{85}$Cl and ${\mathrm{Rb}}^{87}$Cl gives no evidence of a contribution from nuclear electric polarization. In ${\mathrm{Rb}}^{85}$F, the constant of the spin-rotation interaction involving the Rb nucleus $c_1\left({\mathrm{I}}_1·\mathrm{J}\right)$ is $\frac{c_1}{h}=+(0.525\mathrm{}\pm 0.010)$ kc/sec, the constant of the spin-rotation interaction involving the F nucleus $c_2\left({\mathrm{I}}_2·\mathrm{J}\right)$ is $\frac{c_2}{h}=+(10.53\mathrm{}\pm 0.07)$ kc/sec, and the constant of the electron-coupled nuclear dipole-dipole scalar interaction $c_4\left({\mathrm{I}}_1·{\mathrm{I}}_2\right)$ is $\frac{c_4}{h}=+(0.23\mathrm{}\pm 0.06)$ kc/sec. In ${\mathrm{Rb}}^{87}$F, these interaction constants are