Vibrational excitation of polar molecules by electron impact. II. Direct and resonant excitation in H₂O

Abstract

For pt.I see ibid., vol.9, no.14, p.2521 (1976). Differential scattering experiments with the crossed-beam method have been performed to study vibrational excitation of H2O by electron impact for collision energies from threshold to 10 eV. Differential and integral cross sections for the excitation of the (100, 001) and 010 modes are given in absolute units. Two distinct resonance regions are observed which are superimposed on a background of direct excitation: strong and sharp threshold resonances and a broad resonance region centred around 6-8 eV. The broad enhancement of the cross sections around 6 eV is attributed to a very short-lived 2A1 state of H2O-. The threshold resonances are interpreted as quasi-bound states in the dipole field of H2O. They are expected to be of general importance in electron-polar-molecule interactions.

Transport coefficients and cross sections for electrons in water vapour: Comparison of cross section sets using an improved Boltzmann equation solution

“…32 It is important to note that these expressions allow us to account for anisotropic scattering. 1 r For vibrational processes, the cross section set of Seng and Linder, 18 represented by two cross sections corresponding to the fundamental stretching and bending modes, was implemented.…”

“…That work extended but also confirmed (to within experimental uncertainties) the data of El-Zein et al, 16,17 which are rather different from those recommended by Itikawa and Mason 11 but largely consistent with those of Seng and Linder. 18 One of the key discriminating tests on the completeness and accuracy of any given cross section set is provided through electron swarm experiments. [19][20][21] In swarm experiments, electrons are passed through a gas at known pressure and temperature under the influence of a uniform electric field.…”

Analytic Cross Sections for Electron Collisions With Co, Co2, and H2o Relevant to Edge Plasma Impurities

“…The cross sections for the bending (010) (Graph 73) and stretching (100, 001) (Graph 74) modes were measured by Seng and Linder [69] in the energy range from threshold to 10 eV with an uncertainty of ±25%, using a crossed-beam method. They observed a strong and sharp threshold resonance as well as a broad resonance centered around 6-8 eV.…”

Ionization and excitation collision processes of electrons in liquid water

“…As the vibration excitation cross sections q vib , three lump modes, (100 + 001), (010) and others, are considered. The cross sections for (100 + 001) and (010) are constructed by a combination of the data from Seng and Linder (1976) [9] and El-Zein et al (2000) [10] where the cross section around 0.3-6eV is taken from Seng and Linder, and for 6-20eV is from El-Zein et al The summed cross section for the other modes is estimated referring to Märk et al (1995) [11]. The electron attachment cross sections for the production of OH -, O -and H -are taken from Melton (1972) [12].…”