The effect of Vibrational excitation of molecular hydrogen on the dynamics of reaction between O$(^{1}D)$ and H$_{2}$ at ultracold temperatures

The effect of vibrational excitation of H$_2$ molecule on the reactivity of O$(^{1}D)$+H$_{2}$ reaction is explored. A time-independent quantum mechanical approach based on hyperspherical coordinates combined with the potential energy surfaces of Dobbyn and Knowles has been used for the calculation. Energy dependent cross section, probability, and rate coefficients are computed for elastic, inelastic, and reactive channels over collision energies ranging from the ultracold to thermal regimes. Our calculations show that total reaction probabilities, cross sections, and rate coefficients are almost independent of the initial vibrational quantum number of the H$_2$ molecule. The collision outcome is strongly influenced by the intermediate H$_2$O complex formed in the reaction than the initial vibrational quantum number. However, the OH vibrational distribution is found to be sensitive to the initial vibrational level of the H$_2$ molecule. For all three vibrational levels of H$_2$ the reaction is found to populate high rotational levels of OH.