Abstract

We present absolute total photoabsorption cross sections measured with the Very High Resolution Spectrometer at the SURF-II synchrotron radiation source at the National Institute of Standards and Technology, with a resolution of 9 mÅ at 835 Å in the first order. The cross sections of N₂ at the wavelengths of the OΠ(2s2p^4-4P2s²2p^{3 4}S) multiplet are found to be 10 Mb at 834.467 Å, 0.3 Mb at 833.332 Å, and 0.05 Mb at 832.862 Å. This new high-resolution measurement confirms the 10 Mb value, which has given rise to some still-unsolved discrepencies in interpreting atmospheric observations of the OΠ emission.¹ We also measure absolute cross sections in the continua of rare gases, including the argon 3s3p⁶np absorption windows at 425 Å.

© 1992 Optical Society of America