Excited state dynamics of nitrogen reactive intermediates at the threshold of laser induced filamentation

► Laser-induced filamentation was examined using emission spectroscopy. ► Cation and triplet state dynamics were examined. ► Triplet states are populated by intersystem crossing from excited singlet states. ► Neutralization of cations to populate triplet states is a minor pathway. ► Measured electron densities were found to be lower than has been proposed previously.