INELASTIC-SCATTERING OF CL- IONS IN COLLISION WITH H-2 FROM 4 TO 11 EV

We have utilized the time-of-flight (TOF) technique to measure the energy loss of Cl- ions backscattered from H2 in the relative energy region of 4 to 11 eV. For relative energy less than 7 eV, this collision yields vibrational excitation of the H2 molecule and the amount of energy transferred is similar to that in the isoelectronic analog, i.e., K +-H2. In the case of K+, the results were in good agreement with an exact classical calculation involving only the particle masses, the K+-H2 repulsion, and the H2 potential. At higher relative energy (Erel>7 eV), however, the process is much more inelastic with a minimum energy loss of greater than 4 eV, corresponding to dissociation of the H2 molecules. The threshold for dissociation observed here is more commensurate with that predicted for a strong [H2Cl]- surface than with simple T-V transfer kinetics. © 1979 American Institute of Physics.