Low Energy Electron-Hydrogen Scattering

The effective range theory is developed for electron-hydrogen scattering. The scattering length as and the effective range r0s of the singlet state are determined by making use of the accurate solution of the H− ion states, as as = 7.03, r0s = 3.37 (in atomic unit). The scattering length at and the effective range r0t of the triplet state are calculated from the zero energy solution by a variation-perturbation method. The results are at = 2.34, r0t = 1.29.