Charge transfer between nitrogen cations and nitrogen at low energies

The measurement of charge transfer rate coefficients between multiply charged ions and neutral atoms and molecules is important in the areas of plasma physics and astro-physics. Such a measurement is also essential in verifying various theoretical electron capture processes. N2+ is of particular interest since it is abundant in astrophysical nebulas and interstellar molecular clouds. The charge transfer rate coefficient for the charge exchange reaction between N2+ [2s 22p (2P0)] and N2 is measured using ion trap techniques. N2+ ions are produced by electron impact ionization of N2 and stored inside a cylindrical rf trap. The charge transfer rate coefficient is determined by measuring the decay rate of stored N2+ ions in the ion trap. The measured charge transfer rate coefficient between N2+ and N2 is 1.95 +/- 0.27 x 10-9 cm 3 s-1 at Tequiv = 9.1 x 103 K. The estimated uncertainty of +/-14% is mainly due to the statistical fluctuations of the ion signal and the N2 particle density measurements. The charge transfer rate coefficient is within one standard deviation of previously published results.