Voyager has revealed the presence of an extended neutral gas corona on Saturn and Uranus. This observed feature leads to the occurrence of charge-exchange loss of energetic charged particles of the ring current: causing important energetic and dynamic effects in the upper atmospheres of these planets through precipitation. This paper explores the importance of this process in producing H Ly alpha, H alpha, H beta, and H-2 band emissions on the outer planets. This mechanism is found to be an important source of optically thin H Ly alpha emissions from the outer planets. (C) 1997 COSPAR. Published by Elsevier Science Ltd.