Quasiclassical trajectory calculations of Mg(3s3p(1)P(1))+H-2 (v=0, N=1) -> MgH (v, N)+H: Trajectory and angular momentum analysis on improved ab initio potential energy surfaces

In the reaction of Mg(3s3p(1)P(1)) with H-2, we have constructed a new vers ion of ab initio potential energy surfaces (PESs) for 2A' and 1A' states an d their corresponding fit energy functions, on which 50 000 trajectory calc ulations are performed. The improvement of the current quasiclassical traje ctory (QCT) calculations has made dynamical parameters more reliable than t hose reported previously. For instance, the obtained bimodal rotational dis tribution of MgH (v = 0), with a peak ratio of ca. 2:1 for the high-N to lo w-N components, is consistent with the experimental findings. The evaluated vibrational population ratio of ca. 0.52 for v = 1 to v = 0 is also within the range of observation, 0.7 +/- 0.2. In addition, this work provides new information about the formation of MgH rotational levels via the angular m omentum analysis. The trajectory calculations reveals the relation of the r otational distribution to the impact parameter, b, and the relative angle, epsilon, between the orbital and rotational angular momenta of the products . The MgH is preferentially populated in the high-Ar levels at small b but favors the low-N distribution at acute-angle (<90<degrees>) epsilon. The an alysis of vector correlation provides insight into the behavior of the MgH rotational population.