Faculté des sciences

Structures in elastic, vibrational, and dissociative electron attachment cross sections in N₂O near threshold

Allan, Michael ; Skalický, Tomás

In: Journal of Physics B: Atomic, Molecular and Optical Physics, 2003, vol. 36, no. 16, p. 3397-3409

Absolute differential cross sections were measured at 135° for the elastic and the vibrationally inelastic electron scattering from threshold to 12 eV, with emphasis on the threshold region. In addition, relative dissociative electron attachment spectra were measured from 0.1 to 3.5 eV. Structures of vibrational origin were observed at energies below 1 eV, well below the ²Π shape resonance, in... More

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    Summary
    Absolute differential cross sections were measured at 135° for the elastic and the vibrationally inelastic electron scattering from threshold to 12 eV, with emphasis on the threshold region. In addition, relative dissociative electron attachment spectra were measured from 0.1 to 3.5 eV. Structures of vibrational origin were observed at energies below 1 eV, well below the ²Π shape resonance, in the cross sections for the excitation of vibrational overtones and for dissociative attachment. They are generally narrower and deeper than similar structures in CO₂. The structures are absent when the N≡N stretch is co-excited. The structures are interpreted in terms of vibrational Feshbach resonances supported by a state of the anion where an electron is temporarily loosely bound in a spatially diffuse cloud by a combination of dipolar and polarization forces around a molecule with an excited bending and/or N–O stretch vibration.