TOTAL PHOTOABSORPTION CROSS-SECTION OF MOLECULAR NITROGEN NEAR 83.4 NM

The photoabsorption cross section of molecular nitrogen near 83.4 nm h as been measured at room temperature. The cross sections at the wavele ngths of the 2s2p4 P-4(5/2), P-4(3/2), and P-4(1/2) (all - 2s(2)2p3 4S S(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 wer e made with an O+ emission discharge source, and repeated using a sync hrotron radiation source. Both measurements were made with the 0.008-n m resolution 6.65-m spectrometer at the SURF II storage ring of the Na tional Institute for Standards and Technology.