Abstract
The fluorescence of H2 in the Lyman band system, excited by solar extreme ultraviolet radiation, provides a means for the optical detection of H2 in the upper atmosphere. In particular, the Ly β line of hydrogen is nearly degenerate with the (6,0) P1 transition, and absorption in this line produces fluorescence in the v′=6 progression, principally at λλ 1265, 1366, 1462 and 1608 Å. Absorption by 02 rapidly attenuates the Ly β from an overhead sun below 100 km and also significantly attenuates the fluorescent radiation. Farultraviolet dayglow spectra from 1130 to 1510 Å obtained from an Aerobee rocket experiment on 11 December 1972 give an upper limit for any H2 emission which is a factor of 5 higher than expected according to recent hydrogen models.
