The photoabsorption cross section of molecular nitrogen near 83.4 nm has been measured at room temperature. The cross sections at the wavelengths of the 2s2p4 4P5/2, 4P3/2, and 4P1/2 (all -2s22p3 4So3/2) O+ emission lines are measured to be 10.1¿1.6 Mb, 0.29¿0.02 Mb, and 0.049¿0.008 Mb respectively. These measurements were made with an O+ emission discharge source, and repeated using a synchrotron radiation source. Both measurements were made with the 0.008-nm resolution 6.65-m spectrometer at the SURF II storage ring of the National Institute for Standards and Technology. ¿ American Geophysical Union 1993