Combination of plane wave packet and nearside–farside methods applied to the reaction

The plane wave packet (PWP) and nearside–farside approaches are combined, in order to obtain time-dependent differential cross-sections (DCSs) describing the scattering of a plane wave packet over the full θ = 0 → 360° sphere. This produces a better separation of different reaction mechanisms than previous θ = 0 → 180° PWP calculations. Application to the He + H 2 + reaction separates clearly the direct and time-delayed mechanisms, showing that the latter (caused by decay of HeH 2 + scattering resonances) does not begin until the HeH 2 + complex has rotated by over half a revolution, and then continues until the HeH 2 + has described almost an entire revolution. The resulting nearside–farside interference from this decay dominates the (energy-domain) DCS.