Total cross sections of electron scattering by C

Total cross sections for electron scattering by large molecules C4H8O, C5H10O2, C6H5F, C6H5Cl, C6F5Cl, C6H4(CHO)F and C4H8O2 are calculated at the Hartree-Fork level using the modified additivity rule approach. The modified additivity rule approach, which was proposed by Shi et al. [Eur. Phys. J. D 45, 253 (2007); Nucl. Instrum. Meth. B 254, 205 (2007)], takes into consideration that the contributions of the geometric shielding effect vary with the energy of the incident electrons, the target's molecular dimension and the atomic and electronic numbers of the molecule. The present calculations cover the collision energies ranging from 30 to 5000 eV. The quantitative total cross sections are compared with those obtained by experiments and other theories. Good agreement is obtained even at energies of several tens of eV. It shows that the modified additivity rule approach is applicable to calculate the total cross sections of electron scattering by so large molecules at intermediate and high energies, especially above 100 eV. The total cross sections for electron scattering by the C4H8O2 molecule are predicted although no experimental and theoretical data are available for comparison over the present energy region