We employ a parameter-free positron-correlation-polarization (PCOP) potential to calculate total (rotationally summed) cross sections for the positron-${\mathrm{H}}_2$ (${\mathrm{N}}_2$) collisions below the positronium formation threshold energy. A laboratory frame close-coupling technique, retaining six rotational states (j=0,2,4,6,8,10), has been used. It is found that the PCOP model compares reasonably well with measured values. Results on rotationally elastic and inelastic cross sections are also reported. We also make a comparison between PCOP and electron-correlation-polarization models for all the cross sections reported here.

• Received 17 September 1990

DOI:https://doi.org/10.1103/PhysRevA.43.2538