Preferential scattering of one isotopomer over another in (He, HD⁺) collisions

Abstract

Differential cross-section for both the channels of the reaction He + HD⁺ (v=0, 1, 2, 3; j=0)→HeH(D)⁺+D(H) has been calculated using the time-dependent quantum mechanical methodology (helicity basis truncated at k=2) on the Palmieri et al. potential energy surface at relative translational energy E_trans= 1.0 eV. It is shown that HeH⁺ would be formed preferentially over HeD⁺ in the forward direction, while HeD⁺ would be preferred over HeH⁺ in the backward direction for v=1, 2, 3. For v=0, HeH⁺ is scattered preferentially over HeD⁺ in all directions. Therefore, the isotopic branching ratio and its dependence on product scattering angle can be a sensitive probe of the potential energy surface.