Electron-methyl halides scattering. Total cross section measurements for methyl chloride and methyl fluoride

Electron transmission experiments have been carried out in CH 3 F and CH 3 Cl in the energy range between 0.3 and 250 eV. Absolute values for total cross sections are presented and compared with the available data of other groups. The present cross sections are found to be in good agreement with other experiments for CH 3 F in the overlapping range of energies but deviate significantly from prior results in the case of CH 3 Cl. Our present measurements, together with previous ones for CH 3 Br and CH 3 I, confirm the correlation between static electric dipole polarizability of investigated targets and total cross sections at intermediate energies.