ON THE APPEARANCE OF RESONANCES IN REACTIVE SCATTERING - AN EXPERIMENTAL-STUDY OF THE H-2-]HD+D REACTION AT COLLISION ENERGIES NEAR 1.29 EV(D)

The hydrogen exchange reaction H+D-2(v=0,j=0)-->HD(v',j')+D was invest igated at collision energies between 1.27 and 1.30 eV in a high resolu tion crossed beam experiment. The angle-velocity distribution of nasce nt D-atoms was measured using the technique of Rydberg atom time-of-fl ight spectroscopy. The resolution of this technique allows the identif ication of individual ro-vibrational states of the associated HD produ ct molecule. Calculations done on the Liu-Siegbahn-Truhlar-Horowitz (L STH) potential energy surface (PES) explicitly including the Geometric Phase effect predict a resonance in reactive scattering for collision energies close to 1.29 eV. The experimental data do not show signatur es of this resonance in the energy range investigated. Instead of this a general good agreement between experiment and theory even on the ba sis of state-to-state differential cross sections is already found for calculations on the LSTH PES at a collision energy of 1.30 eV not inc luding the Geometric Phase indicating that this effect does not play a n important role at these collision energies. (C) 1997 American Instit ute of Physics.