Ab initio potential energy surface for the reactions between H2O and H

Interpolated ab initio potential energy surfaces which describe abstraction and exchange reactions in collisions of hydrogen and water are reported. The electronic structure calculations are performed at the QCISD(T) level of theory, with an additivity approximation. A sufficiently large basis set is required to describe the Rydberg character of the electronic state for molecular configurations which are important for the exchange process. Classical and quantum dynamics calculations on the surfaces are presented. (C) 2000 American Institute of Physics. [S0021-9606(00)30923-0].