# Hyperfine Structure in Ground Multiplets of $^{17}$O and $^{19}$F

J. S. M. Harvey

## Abstract

The hyperfine structure coupling constants of the ground $^3$P multiplet of $^{17}$O have been measured in a paramagnetic resonance experiment with a sample of enriched oxygen gas. They are: $a_2 = -218.569 \pm 0.004 Mc/s,$ $a_1 = 4.738 \pm 0.036 Mc/s,$ $a_{2,1} = -126.6 \pm 2.0 Mc/s,$ $a_{1,0} = -91.7 \pm 7.2 Mc/s,$ $b_2 = -10.438 \pm 0.030 Mc/s,$ $b_1 = 5.199 \pm 0.090 Mc/s.$ These results confirm the values of a$_2$ and b$_2$ reported previously by Kamper, Lea & Lustig 1957. Measurements have also been made on the excited level of the ground $^2$P multiplet of $^{19}$F. They yield: $a_{\frac{1}{2}} = 10244.21 \pm 0.03 Mc/s.$ $g_J (J = \frac{1}{2}) = 0.66561 \pm 0.00003.$ An analysis of the magnetic hyperfine constants in the ground multiplets of $^{17}$O and $^{19}$F shows that in neither case do they yield consistent values for the two parameters \langle r$^{-3}\rangle$ and $|\psi$(0)|$^2$ usually associated with magnetic hyperfine structure. All measurements of hyperfine structure in these multiplets are consistent, however, with the requirements of LS coupling theory which introduce a third parameter into the magnetic hyperfine operator. The discrepancy is attributed to polarization effects, other than spin polarization of the core s electrons, brought about by the exchange interaction between electrons.