Effective-range analysis of low-energy electron scattering by non-polar molecules

Effective-range theory for electron scattering by non-polar molecules is considered. Low-energy expansions for total and diffusion cross sections are obtained, including terms of the order of k and k 2 ln k which depend on both the polarisability and quadrupole moment. A comparison with the theory of Chang (1978, 1981) is presented. The results are used for the description of experimental data for e-H 2 , N 2 and CO 2 scattering. Comparison with ab initio theoretical results is also given. For the e-CO 2 scattering length in the fixed-nuclei approximation the estimate -7.2<A<-6.8 is obtained.