Vibrational Distribution in Late Nitrogen Afterglows

Abstract

The late portion of long afterglows in nitrogen at a pressure of 1 mm Hg has been investigated spectroscopically, revealing that during 140 sec of decay no change occurs in the characteristic relative vibrational distribution of the N₂ (B ³Π→A ³Σ) 1st positive bands. A common excitation mechanism for all levels is required; it cannot depend upon known metastable particles formed in the initial discharge or generated during the decay.