Absorption Spectrum of the ``Pink'' Afterglow of Nitrogen in the Vacuum Ultraviolet

The absorption spectrum of the short-lived ``pink'' afterglow in nitrogen was photographed in the vacuum ultraviolet from 1600 to 1150 Å. A large number of relatively intense absorption bands were observed. It is suggested that these may result from transitions between the ground state (X 1Σg+) and several excited electronic states (b 1IIu, b′ 1Σu+, and others) in which ground-state vibrational levels of the ground electronic state are populated to very high levels (up to about v″=20). It appears that more than 10% of the nitrogen molecules are excited to vibrational levels greater than v″=8.