Molecular charge transfer reactions of tritium

Abstract

Charge transfer cross sections for the T+2 (X 2Σ+g, v′0) + T2 (X 1Σ+g, v″0) reactions have been computed using multistate eikonal and orbital treatments. Differential cross sections for excitation of individual charge transfer as well as the direct scattering channels were computed as a function of scattering angle and integral cross sections have been determined for incident ions with 0.01 to 5.0 keV kinetic energies. Converged cross sections require the inclusion of a large number of product vibrational states in the wavefunction expansion of the system, with the number increasing to over 100 different vibrational channels as the ion kinetic energy is increased to 5 keV. Differential cross sections for the formation of fast neutral products become more intense and concentrated in the forward direction as the vibrational quantum number of either the reactant ion or target molecule is increased. Integral cross sections involving vibrationally excited neutral target molecules and/or incident ions are larger than those for ground state reactants at low kinetic energies where both energy defects and vibrational overlaps exert a strong influence on the reaction mechanism. Large cross sections involving vibrationally excited species at low kinetic energies is a consequence of the larger number of product channels that are energetically accessible as the reactant vibrational state is increased. At high kinetic energies the vibrational overlaps exert a controlling influence on both tthe magnitude of the charge transfer cross sections and product vibrational state distributions.