DETECTION AF H-3(+) IN INTERSTELLAR SPACE

THE H-3(+) ion is widely believed to play an important role in interst ellar chemistry, by initiating the chains of reactions that lead to th e production of many of the complex molecular species observed in the interstellar medium(1-5). The presence of H-3(+) in the interstellar m edium was first suggested(6) in 1961, and its infrared spectrum was me asured(7) in the laboratory in 1980. But attempts(8-11) to detect it i n interstellar space have hitherto proved unsuccessful, Here we report the detection of H-3(+) absorption in the spectra of two molecular cl ouds. Ali-hough the present results do not permit an accurate determin ation of the H-3(+) abundances, these ions appear nevertheless to be p resent in sufficient quantities to drive much of the chemistry in mole cular clouds, It should soon be possible to obtain more accurate measu rements, and thus better quantify the role of ion-neutral reactions in the chemical evolution of molecular clouds.