Electric dipole moment and charge transfer in alkali-C molecules

Electron excitation rate coefficients for 2p (2p₁, 2p₂, 2p₃, 2p₄, 2p₅, 2p₆) and 3p(3p₅, 3p₆, 3p₇, 3p₈, 3p₁₀) (in Paschen notation) levels of xenon atom have been measured by using electron drift tube technique. The absolute excitation coefficients were obtained from the optical signal at the anode in Townsend xenon discharges, after correction for detector quantum efficiency. The ionization coefficients were determined from the spatial emission profile. The measurement were made for the electric field to xenon atom number density ratios (E/N) from Vm² to Vm². The data were obtained between moderate E/N values where electrons are in equilibrium and very high E/N values where electrons may not be in equilibrium with the local field. It was found that at the highest values of E/N heavy particles do not contribute to the excitation under the present conditions. The absolute excitation coefficients for the studied levels of xenon are to our knowledge the only experimental data available in the literature. Received 17 March 1999 and Received in final form 9 August 1999