Differential cross sections for electron impact excitation of the n = 2 states of helium at intermediate energies (80, 100 and 120 eV) measured across the complete angular scattering range (0180°)

R Ward (1) , D Cubric (1) , N Bowring (1) , G C King (1) , F H Read (1) , D V Fursa (2) , I Bray (2) , O Zatsarinny (3) , K Bartschat (3)

1 School of Physics and Astronomy, Schuster Laboratory
2 ARC Centre for Antimatter-Matter Studies
3 Department of Physics and Astronomy [Des Moines]

Differential cross sections for n = 2 states of helium at intermediate energies (80 eV, 100 eV and 120 eV) measured across the complete angular scattering range (0°-180°). Differential cross sections for electron impact excitation of the n = 2 states of helium at intermediate energies (80 eV, 100 eV and 120 eV) measured across the complete angular scattering range (0°-180°). Abstract Differential cross sections (DCS) for inelastic electron scattering to the n = 2 states in helium have been measured at incident energies of 80 eV, 100 eV and 120 eV. These DCS have been determined across the complete angular scattering range (0° to 180°) using a magnetic angle changer (MAC) with a soft-iron core. The converging close-coupling (CCC), R-matrix with pseudostates (RMPS), and B-spline R-matrix (BSR) methods have been used to calculate these DCS. Agreement between the experimental data and the predictions from these highly sophisticated theoretical methods is generally good. The remaining discrepancies mainly occur at small and large angles for the triplet states 2 3 S and 2 3 P, whereas excellent agreement is found between 30º-150º. The small-angle differences are likely due to contamination of the observed experimental signal from the neighbouring 2 1 S and 2 1 P states. The present results demonstrate the effective use of a soft-iron core magnetic angle changer for DCS measurements at intermediate energies, extending the operational energy range of such devices by a factor of approximately 25.. 4 Corresponding Author. Differential cross sections for n = 2 states of helium at intermediate energies (80 eV, 100 eV and 120 eV) measured across the complete angular scattering range (0°-180°). numbers: 34.80.Dp Atomic excitation and ionisation 34.10.+x General theories and models of atomic and molecular collisions and interactions (including statistical theories, transition state, stochastic and trajectory models, etc.) Differential cross sections for n = 2 states of helium at intermediate energies (80 eV, 100 eV and 120 eV) measured across the complete angular scattering range (0°-180°).

Mots clés: Physical Sciences

R Ward, D Cubric, N Bowring, G C King, F H Read, et al.. Differential cross sections for electron impact excitation of the n = 2 states of helium at intermediate energies (80, 100 and 120 eV) measured across the complete angular scattering range (0180°). Journal of Physics B: Atomic, Molecular and Optical Physics, 2011, 44 (4), pp.45209. ⟨10.1088/0953-4075/44/4/045209⟩. ⟨hal-00596623⟩