6.1 Total scattering cross sections

Cross Sections for Electron Collisions with Acetylene

“…Data due to Szmytkowski et al, 33 Xing et al, 36 and Ariyasinghe and Powers. 37 Karwasz et al 41 differ. For the 1-100 eV energy region, averaging different experiments does not seem a proper way to get recommended cross sections: Brüche's points show a big spread, the measurement of Dressler and Allan 35 is normalized in a rather arbitrary way, the TCS of Sueoka and Mori was obtained with a poor energy resolution.…”

“…The energy resolution was relatively poor, 1 eV FWHM, but the energy scale was determined intrinsically by the time-of-flight method. Measurements at 1-6 eV were performed with 3 G magnetic field and at higher energies-at 4.5 G. As shown by Karwasz et al 41 in the case of a guiding magnetic field, a geometrical definition of the angular resolution does not properly characterize possible systematic errors. This is rather a ''radius of gyration'' smaller than exit aperture radius which should be considered: electrons scattered at lower angles are counted as non-scattered, lowering the measured TCS.…”

“…1. In the previous analysis by Karwasz et al, 41 the data of Dressler and Allan were used to determine the TCS below 1 eV. In that case, the data were normalized to the results of Sueoka and Mori.…”

“…As a consequence, the present recommended and those from the work of ; the absolute TCS of Sueoka and Mori 34 at 5-15 eV has been renormalized by 110% and at 16-100 eV by 15%, on the basis of a possible angular resolution error, elastic differential cross sections of Gauf et al 42 have been used for this evaluation. The short broken line is the earlier set of recommended TCS, 41 based on measurements of Sueoka and Mori 34 and Dressler and Allan 35 normalized to the previous ones. Data due to Szmytkowski et al, 33 Xing et al, 36 and Ariyasinghe and Powers.…”

LSPM J1314+1320: An Oversized Magnetic Star with Constraints on the Radio Emission Mechanism

“…For the contribution from collisions between electrons and neutral hydrogen, we use the results of Temkin & Lamkin (1961) and Fon et al (1978) for the total elastic scattering cross section. For collisions between electrons and H2 molecules, we use the cross section data of Karwasz et al (2003) tabulated by Yoon et al (2008). Accurate fits to the resulting magnetic diffusivities over the temperature range 10 and electrons, respectively.…”