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We report a joint theoretical-experimental investigation of electron collision with dimethyl ether (DME) in the low-and intermediate-energy ranges. Experimental absolute differential, integral, and momentum-transfer cross sections for elastic e − -DME scattering are reported in the 100-1000 eV energy range. Our measurements were performed using a crossed electron-beam-molecular-beam geometry. The angular distribution of the scattered electrons was converted to absolute cross section using the relative flow technique. Theoretically, elastic differential, integral, and momentum-transfer cross sections, as well as the grand-total and total absorption cross sections for electron collision with DME are calculated in the 1-1000 eV energy range. A single-center-expansion technique combined with the Padé approximant method is used in our calculations. A comparison between the present experimental and theoretical data shows very good agreement. Moreover, comparison with theoretical and experimental data for e − -ethanol (an isomer of DME) scattering shows interesting isomeric effects.

Calculated elastic differential, integral, and momentum transfer cross sections as well as total ͑elastic ϩ inelastic͒ cross sections for electron-CH 4 collisions are reported in the (20-500)-eV energy range. Four model potentials of both a nonempirical and semiempirical nature are used to represent absorption effects. The Schwinger variational iterative method combined with the distorted-wave approximation is used to solve the scattering equations. Through the comparison of our calculated results with available experimental data, two of these model absorption potentials are recommended as more convenient for treating electron-molecule collision problems.

The method of continued fractions (MCF) of Horáček and Sasakawa is applied for the first time to the study of low-energy electron scattering by linear molecules at the twostate close-coupling level. In particular, we have calculated the excitation cross sections for the transition X 1 + g → b 3 + u in H 2 for incident energies from near threshold to 40 eV. In contrast to the early two-state studies of Chung and Lin, in this work no orthogonality constraint between the bound and continuum orbitals is imposed and the one-electron exchange terms are considered explicitly. The calculated cross sections are in very good agreement with the available experimental data and with some recent theoretical results.

The distorted-wave approximation is applied to study electron-impact excitation leading to the , , and states of CO in the 20 - 100 eV range. Our calculated DCS and ICS are compared with available theoretical and experimental data. In general our cross sections are in quite good agreement with previous two- and five-state Schwinger multichannel results. Also, good qualitative agreement with the experimental data is obtained. However, in general our theory overestimates the cross sections. In comparison with a previous DWA study, our work reveals the strong influence of the description of the target wavefunctions on the calculated cross sections.