Secção de choque total absoluta do espalhamento de elétrons por Metanol e Etanol

Abstract

We have measured the absolute Total Cross Section (TCS) for methanol and ethanol molecules using an apparatus manufactured at the Molecular Spectroscopy Laboratory at DF/UFJF, which employ the linear transmission technique. The experimental data were taken at incident electron energies of 70, 80, 90, 100, 150, 200, 250, 300, 350, 400 and 500 eV for methanol and ethanol and also of 60 eV for ethanol. The energy resolution in all measurements was 0,6 eV (FWHM) and the overall systematic uncertainty at the TCS were evaluated to be less than 5%. The pressure range in the scattering cell was chosen between 1 and 4mTorr. Those electrons which passed the exit orifice of the chamber were discriminated with a 127o cylindrical energy selector coupled with an entrance set of electrostatic lenses and detected by a Faraday cup. Measuring the attenuation of intensity of the projectile-particle beam transmitted through the target volume, the absolute TCS for a given impact energy was derived from the Beer-Lambert law. The measurements were carried out for a given energy in a series of alt least 4 runs, each one taking at least 7 values and an averaging procedure was applied to derive the final total cross section at a particular energy. Besides the experimental measurements, we have additionally determined TCS using the Additivity Rule. We have also evaluated our experimental data using a fitting procedure with the Born-like formula containing two parameters for each gas. Our experimental data are in good agreement with the majority of previous measurements published in the literature. There are no previous reports of experimental electron scattering Total Cross Section C2H5OH in the literature.