Molecular Physics of Elementary Processes Relevant to Hypersonics: Electron-Molecule Collisions

Abstract

Non-resonant, electron-impact, vibro-electronic excitation cross sections, involving vibrationally excited N 2 molecules, to the mixed valence-Rydberg b,c,o 1 Π u and ′ b , ′ c , ′ e 1 Σ u + singlet states are presented. These cross sections are calculated using the so-called similarity approach, accounting for the vibronic coupling among excited states, and compared with the experiments and different theoretical calculations. New cross sections for the electron-impact resonant vibrational excitation of CO 2 molecule are calculated, for the symmetric stretching mode, as a function of the incident electron energy and for the transitions (υ i ,0,0) → (υ f ,0,0) with υ i = 0,1,2 and for some selected value of υ f in the interval υ i ≤ υ f ≤ 10. A resonance potential curve and associated widths are calculated using the R-matrix method. Rate coefficients, calculated by assuming a Maxwellian electron energy distribution function, are also presented for the same (υ i ,0,0) → (υ f ,0,0) transitions. Electron-impact cross sections and rate coefficients for resonant vibrational excitations involving the diatomic species N 2 , NO, CO, O 2 and H 2 , for multi-quantic and mono-quantic transitions, are reviewed along with the cross sections and rates for the process of the dissociative electron attachment to H 2 molecule, involving a Rydberg excited resonant state of the ion.