Positron total cross sections for collisions with O 2 , H 2 O and CH 4 in energy range from 30 to 3000eV

Abstract

Total (elastic plus inelastic) cross sections (TCSs) for the scattering of positrons by molecules O2, H2O and CH4 in the energy range from 30 to 3000eV are calculated using the additivity rule model at Hartree–Fock level. A complex optical model potential modified by incorporating the concept of bonded atom which takes into consideration the overlapping effect of electron clouds between two atoms in a molecule is firstly employed for the TCS calculation of positron–molecule scattering. TCSs are quantitatively compared with those obtained in experiments and other theories wherever available and good agreement is obtained in the energy range from 30 to 3000eV. It is shown that the additivity rule model together with the modified complex optical model potential is completely suitable for the TCS calculations of the positron–molecule scattering.