We report an investigation on electron collisions with two nitrogen-containing compounds, namely ammonia (NH 3 ) and formamide (NH 2 CHO). For ammonia, both theoretical and experimental differential, integral, and momentum-transfer cross sections, as well as calculated grand-total and total absorption cross sections, are reported in the 50-500 eV incident energy range. Calculated results of various cross sections are also reported for energies below 50 eV. Experimentally, angular distributions of the scattered electrons were measured using a crossed electron beam-molecular beam geometry and then converted to absolute differential cross sections using the relative flow technique. Absolute integral and momentum-transfer cross sections for elastic e − -ammonia scattering were also derived from the measured differential cross sections. For formamide, only theoretical cross sections are presented in the 1-500 eV incident energy range. A single-center-expansion technique combined with the method of Padé was used in our calculations. For both targets, our calculated cross sections are compared with the present measured data and with the theoretical and experimental data available in the literature and show generally good agreement. Moreover, for formamide, two shape resonances located at 3.5 eV and 15 eV which correspond to the continuum 2 A and 2 A scattering symmetries, respectively, are identified. The former can be associated to the 2 B 1 shape resonance in formaldehyde located at around 2.5 eV, whereas the latter can be related to the 2 E resonance in ammonia at about 10 eV. Such correspondence is very interesting and so supports the investigation on electron interaction with small building blocks, instead of with larger biomolecules.

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.

We report a joint theoretical-experimental investigation of elastic electron scattering by dimethyl sulfide in the low-and intermediate-energy regions. More specifically, experimental differential, integral, and momentumtransfer cross sections are given in the 30-800 eV and 10°-130° ranges. Theoretical cross sections are reported in the 1-500 eV interval. The experimental differential cross sections were determined using a crossed electronbeam-molecular-beam geometry, whereas the absolute values of the cross sections were obtained using the relative-flow technique. Theoretically, a complex optical potential was used to represent the collision dynamics, and a single-center expansion method combined with the Pade approximant method was used to solve the scattering equations. Our experimental data are in good agreement with the present calculated data but strongly disagree with those reported in a previous investigation.

We report a theoretical study on electron scattering by two strongly polar molecules, namely, formaldehyde (CH 2 O) and pyrimidine (C 4 H 4 N 2 ), in the low-and intermediate-energy ranges. Calculated elastic differential, integral, and momentum-transfer cross sections, as well as total (elastic + inelastic) and total absorption cross sections, are reported for impact energies ranging from 0.2 to 500 eV. A complex optical potential is used to represent the electron-molecule interaction dynamics, whereas a single-center-expansion method associated with the Padé approximant technique is used to solve the scattering equations. Our calculated results are compared with experimental results and other theoretical data available in the literature. Generally good agreement is seen in these comparisons.

We report a joint theoretical-experimental investigation on elastic electron scattering by acetone in the low-and intermediate-energy regions. More specifically, experimental differential, integral, and momentum-transfer cross sections are given in the 30-800 eV and 10 • -120 • ranges. Theoretical cross sections are reported in the 1-500 eV interval. The experimental differential cross sections were determined using a crossed electron-beam-molecularbeam geometry, whereas the absolute values of the cross sections were obtained using the relative-flow technique. Theoretically, a complex optical potential derived from a Hartree-Fock molecular wave function was used to represent the collision dynamics, and a single-center expansion method combined with the Padé approximant technique was used to solve the scattering equations. Our experimental cross-section data are in generally good agreement with the present calculated data. Also, our calculated grand-total and total absorption cross sections are in good agreement with the experimental results reported in the literature. Nevertheless, our calculations have revealed a strong shape resonance in the 2 B 2 scattering channel not clearly seen in the experimental results. Possible reasons for this fact are also discussed.