Low energy (0.01-20 eV) electron scattering from acetylene

We report elastic differential, integral and momentum transfer cross sections for the electron-C 2 H 2 system in the energy range of 0.01-20 eV. A parameter-free model potential approach is employed under the fixed-nuclei, single-centre, and close-coupling formalism. The electron exchange interaction is treated via a modified version of the semi-classical exchange model, while the short range correlation and long range polarization effects are included under the correlation-polarization approximation. This local and non-empirical potential, for both the exchange and charge distortion effects, is very successful in describing the 2 Pi g shape-resonance phenomenon around 2 eV. Our final results for both the differential and integral cross section compare very well with recent measurements. A Ramsauer-Townsend minimum is found around 0.2 eV in the total and momentum transfer cross sections.