Close-coupling scattering cross sections and a model for positron cooling in a buffer gas of molecular nitrogen

Cross sections for positron scattering from molecular nitrogen are reported for energies below the positronium formation threshold. The elastic and state-to-state rotational and vibrational cross sections were obtained within the close-coupling formalism, using a three-dimensional potential energy surface for the interaction of the system. The inelastic cross sections was involved in a kinetic model to describe recent experimental results about positron cooling in a buffer gas of molecular nitrogen. Unlike a previous model [M. R. Natisin et al., J. Phys. B 47, 225209 (2014)], our prediction attributes a leading role to the 0 -> 1 vibrational excitation of N-2.