In-flight radiative decay and collision-induced ionization of N

Abstract

Highly excited fragments (${\mathrm{N}}^{**}$) from electron-impact dissociation of ${\mathrm{N}}_{2}$ are studied in a time-of-flight technique. By using a sophisticated vacuum-ultraviolet filter technique we can show that more than 50% of the fragments in the atomic beam are Rydberg atoms belonging to the quartet system and more than 20% are doublet Rydberg atoms. We also succeeded in ending a controversy over the $\mathrm{N}^{6}S$ state: As it is not detectable in the meta-stable beam, its lifetime has to be considerably shorter than 10 \ensuremath{\mu}s because effective population of this state by electron impact seems to be very likely. From collisions of Rydberg atoms with several target gases, especially S${\mathrm{F}}_{6}$, we learn that ${\mathrm{N}}^{+}$ formation proceeds according to $\ensuremath{\sigma}\ensuremath{\propto}\frac{1}{v}$ within the range 1-5 eV of collisional energies. We also give absolute cross sections for the ${\mathrm{N}}^{**}$ destruction by several electronegative gases.