On the appearance of resonances in reactive scattering: An experimental study of the H+D2→HD+D reaction at collision energies near 1.29 eV

Abstract

The hydrogen exchange reaction H+D2(v=0,j=0)→HD(v′,j′)+D was investigated at collision energies between 1.27 and 1.30 eV in a high resolution crossed beam experiment. The angle-velocity distribution of nascent D-atoms was measured using the technique of Rydberg atom time-of-flight spectroscopy. The resolution of this technique allows the identification of individual ro-vibrational states of the associated HD product molecule. Calculations done on the Liu–Siegbahn–Truhlar–Horowitz (LSTH) 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 signatures of this resonance in the energy range investigated. Instead of this a general good agreement between experiment and theory even on the basis 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 including the Geometric Phase indicating that this effect does not play an important role at these collision energies.

Strong geometric-phase effects in the hydrogen-exchange reaction at high collision energies: II. Quasiclassical trajectory analysis

“…Later work by Kuppermann and co-workers [5], [55]- [58] using multivalued basis functions approach to include the GP, considered more general effects where the unsymmetrized wave function may encircle the CI. Their calculations predicted strong GP effects in the differential cross sections (DCS), but these predictions were neither reproduced by later calculations that omitted the GP [9,11,24], nor by experiments [8,10]. Detailed experimental results agreed quantitatively well with theoretical predictions ignoring the GP boundary condition.…”

Simultaneous Measurement of Reactive and Inelastic Scattering: Differential Cross Section of the H + HD → HD(v′, j′) + H Reaction

“…Calculations by Kuppermann and co-workers in the early 90s predicted significant differences in experimental observables between calculations ignoring and including the GP effect [47,48]. Experimental measurements however were a very good fit to theory that did not take the GP into account [2,[7][8][9]12,49]. Following earlier work by Kendrick [50], Althorpe and co-workers [33,37,38,51,52] succeeded in proving definitively that the GP has no effect on the ICS and only a minor effect on the DCS at E coll < ∼ 4 eV.…”

“…Indeed, this is part of the reason why the reactive scattering of the H + D 2 and D + H 2 reactions has received considerably more experimental attention than the inelastic process. It is well known that reactive encounters between a hydrogen atom and a hydrogen molecule are mostly direct in nature [1][2][3][4][5][6][7][8]. According to this model, small-impactparameter collisions lead to rotationally cold, backward scattered products, while glancing, large-impact-parameter collisions produce rotationally excited, sideways/forward scattered products.…”

Non‐Adiabatic Effects in Chemical Reactions: Extended Born‐Oppenheimer Equations and its Applications

“…Satisfactory agreement between experimentally measured and theoretically (without considering the GP effect) calculated results [80,[82][83][84][85][86][87] for the reaction, H þ D 2 ðv ¼ 0; j ¼ 0Þ ! HDðv 0 ; j 0 Þ þ D, at a collisional energy of 2.20 eV has renewed theoretical interest in this area.…”