Dissociative recombination in krypton: Dependence of the total rate coefficient and excited-state production on electron temperature

Microwave afterglow and grating spectrometric apparatus are used to study dissociative recombination in krypton. Over the electron temperature range 300≤Tₑ≤8400 K and with T₊=Tgas=300 K, the total rate coefficient may be represented by α[Kr₂⁺]=1.6×10^-6[300Tₑ(K)]0.55 cm³/sec, with an uncertainty of ±{} 10%. At thermal energy (300 K) excited states of Kr* having energies up to that of the Kr₂⁺ ion in its ground electronic and vibrational state are observed to result from the dissociative recombination. With microwave heating to Tₑ~7000 K, additional, higher-lying Kr* states (up to {~} 0.5 eV above the Kr₂⁺ ion ground state) are observed. In both cases the excited states most strongly populated by dissociative recombination appear to be the $5p$ states.