Theoretical study of the isotope effects in the non-adiabatic reaction of AR+(J) with H2, D2, HD

We use a wavepacket method to investigate isotope effects on the reactive collision between an Ar+ ion in a well defined spin orbit state and the isotopes of the hydrogen molecule: H-2, HD and D-2 in their ground rovibronic state. The collision energy range is 0.3 to 5 eV. Because eight electronic states play a role during this non-adiabatic reaction, a number of approximations have been made: Use of the diatomic in molecule method to determine the diabatic potential energy surfaces and couplings, semi-classical and coplanar approximation in the treatment of the dynamics. The total reaction cross section are obtained and compared the to the available experimental data. We also present the first state-to-state reaction cross sections for these systems. Finally, the results are analysed in terms of reaction mechanism. (C) 1998 Elsevier Science B.V.