Elastic Scattering of Low-Energy Electrons by Argon

The partial-wave Schrödinger equation has been integrated numerically for a potential adjusted so that the predicted elastic scattering is in agreement with measurements by Ramsauer and Kollath. The cross section at zero energy is found to be 8×${10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$ which is appreciably above the minimum value of 0.3×${10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$ at 0.4 ev. The high value at zero energy, which results from the tail of the polarization force, will be reduced at densities of one atmosphere and above, because the field is cut off by neighboring atoms. Application of the method to predict the eigenvalues of the excited bound states of potassium indicates the validity of the static potential and that the exchange force decreases with increasing angular momentum.