GENERATION OF AN H-3(+)(NU=0) BEAM AND ITS DIAGNOSIS FROM THE OBSERVATION OF ITS POLAR DISSOCIATION IN COLLISION WITH HE

Ground state H-3(+) ions in their lowest vibrational level were produc ed, and the initial vibrtaional state of the H-3(+) ions was qualitati vely observed as a function of the source pressure. Quantitatively, th e polar dissociation channel was studied in order to verify the initia l vibrational state of the ions. The energy distributions of H+ and H- , generated from the collisional dissociation of H-3(+) in He at 9 keV of projectile energy, resulting from the polar dissociating channel, were measured in coincidence. The good agreement between the center of mass energy threshold of the proton distributions from the polar diss ociation process and the theoretical potential curves for the adiabati c Born-Oppenheimer energies of the H-3(+) ions confirms the vibrationa l cooling of the H-3(+) beam by operating the ion source at high press ure. We conclude that the process is effectively originated from H-3()(v = 0). (C) 1997 Elsevier Science B.V.