Potential energy surface for the reactions BeH2+H reversible arrow BeH+H-2

An ab initio surface for these reactions has been obtained at the MP2/6-311 G(d,p) level of theory. The surface is given by an interpolation of second order Taylor expansions at 438 molecular configurations. The accuracy of th e interpolation and of this level of ab initio theory are examined. The sur face has the full molecular symmetry and classical trajectories show that e xchange reactions compete with both forward and reverse abstraction reactio ns.