TOTAL PHOTOABSORPTION CROSS-SECTION OF MOLECULAR NITROGEN NEAR 83.4 NM

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 P-4(5/2), P-4(3/2), and P-4(1/2) (all - 2s(2)2p3 4SS(o)3/2) 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.