The role of vibrational coupling in low-energy positron scattering from molecular targets

The effect of dynamically coupling the motion of the impinging positron with that of the molecular nuclei during the scattering process is examined. At the collision energies below the threshold of positronium formation one finds that the effects are increasing the size of the total integral cross sections but are different at different energies. Comparison with experiments is carried out for the CO2 target and shows rather good agreement between calculations and the available measurements. The presence of a threshold peak in the inelastic channel is also discussed in analogy with the case of electron scattering from the same molecule.