Secondary “pink afterglow” in post-discharge in pure nitrogen

Abstract

The DC post-discharge in pure nitrogen was studied in a Pyrex discharge tube with molybdenum hollow electrodes at the pressure of 980 Pa and the discharge current of 160 mA. Besides the emission enhancement at the pink afterglow position at about 5 ms that is about 20 times lower in this case, the secondary intensity maximum at about 24 ms was observed. This effect can be recognized for all the observed nitrogen spectral systems, but with a different intensity. It is also interesting that in this new post-discharge regime, the first positive system emission is higher than in the normal post-discharge at the decay times longer than about 18 ms. The possible kinetic model of these observations is included, too. The main role in the kinetics is probably played by the changes of the wall conditions due to some thin layer deposited at the reactor wall during the recent nitrogen-oxygen measurements.