Université de Fribourg

New light on the Kr⁻(4p⁵5s²) Feshbach resonances: high-resolution electron scattering experiments and B-spline R-matrix calculations

Hoffmann, T. H. ; Ruf, M.-W. ; Hotop, Hartmut ; Zatsarinny, O. ; Bartschat, K. ; Allan, Michael

In: Journal of Physics B: Atomic, Molecular and Optical Physics, 2010, vol. 43, no. 8, p. 085206

In a joint experimental and theoretical effort, we carried out a detailed study of electron scattering from Kr atoms in the energy range of the low-lying Kr⁻($4p^5 5s^2$) Feshbach resonances. Absolute angle-differential cross sections for elastic electron scattering were measured over the energy range 9.3–10.3 eV with an energy width of about 13 meV at scattering angles between 10° and...

Université de Fribourg

Low-energy electron attachment to the dichlorodifluoromethane (CCl₂F₂) molecule

Graupner, K. ; Haughey, S. A. ; Field, T. A. ; Mayhew, C. A. ; Hoffmann, T. H. ; May, Olivier ; Fedor, Juraj ; Allan, Michael ; Fabrikant, Ilya I. ; Illenberger, E. ; Braun, M. ; Ruf, M.-W. ; Hotop, Hartmut

In: The Journal of Physical Chemistry A, 2010, vol. 114, no. 3, p. 1474–1484

Results from a joint experimental study of electron attachment to dichlorodifluoromethane (CCl₂F₂) molecules in the gas phase are reported. In a high resolution electron beam experiment involving two versions of the laser photoelectron attachment method, the relative cross section for formation of the dominant anion Cl⁻ was measured over the energy range 0.001−1.8 eV at the gas...

Université de Fribourg

Resonance structure in electron–N₂ scattering around 11.5 eV: high-resolution measurements, ab initio calculations and line shape analyses

Hoffmann, T. H. ; Allan, Michael ; Franz, K. ; Ruf, M.-W. ; Hotop, Hartmut ; Sauter, G. ; Meyer, W.

In: Journal of Physics B, 2009, vol. 42, no. 21, p. 215202

Using two different experimental setups with energy widths of about 6 and 13 meV, we obtained significantly improved results for the energy dependence of angle-differential (10°–180°) elastic and vibrationally inelastic cross sections for electron scattering from N₂ molecules in the energy range around the narrow N⁻₂(R²Σ⁺g) resonance. The energy location and the natural...

Université de Fribourg

Resonance structure in low-energy electron scattering from OCS

Hoffmann, T. H. ; Hotop, H. ; Allan, Michael

In: Journal of Physics B: Atomic, Molecular and Optical Physics, 2008, vol. 41, no. 9, p. 195202

Energy-dependent absolute angle-differential cross sections (θ = 135°) for elastic and vibrationally inelastic electron scattering from OCS molecules have been investigated at high resolution (13 meV). The elastic cross section, reported over the range E= 0.06–20 eV, exhibits a deep Ramsauer–Townsend minimum near 0.55 eV and the π*(1.2 eV) and σ*(3.8 eV) resonances known from...

Université de Fribourg

Low-lying resonances in electron-argon scattering: Measurements at 5-meV resolution and comparison with theory

Franz, K. ; Hoffmann, T. H. ; Bömmels, J. ; Gopalan, A. ; Sauter, G. ; Meyer, W. ; Allan, Michael ; Ruf, M.-W. ; Hotop, H.

In: Physical Review A, 2008, vol. 78, no. 1, p. 012712

Combining a laser photoelectron source with a triply differentially pumped supersonic beam target and several electron multipliers for simultaneous detection of electrons elastically scattered into the angles 22.5°, 45°, 90°, 112.5°, and 135° and of metastable atoms due to inelastic scattering, we have carried out an improved study of electron-argon scattering over the energy range...