A Note on the Extrapolation of Atomic Structure Factor Curves

An approximate extrapolation formula for atomic structure factors of high order has been deduced from the form of the electron distributions indicated by the wave equation. The result is compared with the structure factors determined from ${\mathrm{H}\mathrm{a}\mathrm{r}\mathrm{t}\mathrm{r}\mathrm{e}\mathrm{e}\text{'}\mathrm{s}}^1$ electron distribution for ${\mathrm{Na}}^{+}$. The agreement is good enough to warrant the use of the formula in extrapolating experimentally determined structure factor curves. It is shown that an analogous treatment can be applied to the "$S$" curves obtained from the scattering of x-rays by gases.