Isotope effects on the dynamics in the ion-diatomic collisions of D+, H+ with H2 and D2 molecules

The isotope effect on integral cross section and product rotational polarization has been investigated for title reactions D+ + H2 and H+ + D2 by quasiclassical trajectory method. The calculated results show the isotope effect on the integral cross section is weak at low collision energy but remarkable at high collision energy. However, the rotational polarization of the product HD molecule is sensitive to the mass factor at low collision energy of 0.524 eV. The initial vibrational excitation plays a more important role in the anisotropic distribution of the product angular momentum vector for the reaction D+ + H2 than that for the reaction H+ + D2.