Excitation, dissociation and ionization by electron impact of diatomic molecules either in their ground state or in an electronically and vibrationally excited state represent some of the main elementary processes affecting the behavior of many plasmas and gaseous systems of technological and scientific interest. Theoretical description of the plasma kinetics or experimental determination of quantities like the electron and vibrational distribution functions, electron temperature and transport properties require, as a consequence, the knowledge of wide sets of electron impact cross sections data resolved in terms of both initial and final vibrational spectrum for a large number of electronic transitions. Therefore, the knowledge of state-to-state cross sections for excitation and dissociation and other elementary processes, induced by electron impact on vibro-electronically excited diatomic molecules, represents a basic information both in the theoretical simulations and experimental studies of low temperature plasmas. Typical examples are given by H₂ plasmas used in nuclear fusion (negative ion sources, divertors plasmas) or N₂ and O₂ gaseous systems studied in atmospheric and rientry problems.
In this communication the following state-to-state electronic transitions for H₂ and N₂ molecules will be considered:
- H₂ triplet-triplet(1) and singlet-triplet excitations: a³Σ_g⁺ → d³Π_u; c³Π_u → h³Σ_g⁺; c³Π_u → g³Σ_g⁺; X¹Σ_g⁺ → d³Π_u; X¹Σ_g⁺ → a³Σ_g⁺
- N₂ singlet-singlet excitations: X¹Σ_g⁺ → b¹Π_u; X¹Σ_g⁺ → b’¹Σ_u⁺

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