Spectra are presented from flowing afterglows in N2produced by a microwave discharge. The luminescence from pure N2discharges can be characterized as a typical Lewis‐Rayleigh afterglow with no molecular emission in the ultraviolet. Trace amounts of SF6added upstream of the discharge greatly enhance the first‐positive emission from the afterglow and produce intense emission from the N+2first‐negative system and the appearance of N2second‐positive emission. Further SF6addition downstream of the microwave discharge quenches the N+2first‐negative bands but causes no appreciable change in the emission from the N2second‐positive bands. Increasing the SF6added prior to the discharge by a factor of 15 results in complete quenching of all N2ultraviolet emission which is replaced by NSB‐Xluminescence.