TOTAL CROSS SECTIONS FOR THE DESTRUCTION OF H3+ (v=0) ON He I. Alvarez, F. B. Yousif, G. Hinojosa ,C. Cisneros, J. de Urquijo Centro de Ciencias Fisicas, UNAM, P.O. Box 48-3, Cd. Post. 62251 Cuernavaca, Mor., Mexico Total cross sections for the positive and negative fragments originated from the dissociative excitation of H3+ and in their ground state in the energy range 3-9 keV have been measured. The cross sections were found to decrease by about one order of magnitude from those taken with vibrationally excited molecules than those with vibrationally cold molecules.