Altitude profiles of the O+ 834-¿ emission, obtained from rocket observations at moderate and high solar conditions, are compared with model calculations. The model showed that when viewing the atmosphere horizontally at altitudes below the F2 layer, the 834-¿ intensity was virtually independent of the O+ density. The 834-¿ intensity was found to be highly sensitive to the N2 absorption cross section. Comparisons with model calculations suggest that absorption by N2 is a factor of 10 lower than the currently accepted values. Agreement between calculated and observed intensities was obtained by adjusting the N2 cross sections to 1¿10-19, 4¿10-19, and 1.2¿10-18 cm2 at the O+ triplet wavelengths of 832.75 833.33, and 834.46 ¿, respectively. This adjustment was required in order to simulate the overlap between rotational absorption lines of N2 and the O+ emission lines. ¿ American Geophysical Union 1989