Ion trap study of the isotope exchange in the low-temperature collisions of OD^- anions with HD

The rate coefficients k(1) and k(2) of the reaction OD + HD paired right arrows(k1)(k2) OH + D-2 in the forward and reverse direction were measured in the temperature ranges of 15 K-273 K and 95 K-300 K, respectively. The experiments were carried out in a temperature-variable cryogenic linear 22-pole radio-frequency ion trap instrument. The temperature dependence of the equilibrium constant K-eq12(T) obtained from the measured data is in good agreement with the value calculated using the detailed balance principle under the Born-Oppenheimer approximation. The enthalpy and the entropy of the reaction obtained from the linear Van't Hoff equation are Delta H = (20 +/- 2 +/- 3(sys)) meV and Delta S = (5.9 +/- 1.8 +/- 1.4(sys)) J/mol K, respectively. [GRAPHICS] .