  This paper presents two new adiabatic, global potential energy surfaces
(PESs) for the two lowest $^3A'$ and $^3A''$ electronic states of the
O($^3P$)+H$_2$ system. For each of these states, ab initio electronic energies
were calculated for more than 5000 geometries using internally contracted
multireference configuration interaction methods. The calculated points were
then fitted using the ansatz by Aguado et al. [Comput. Phys. Commun. 108, 259
(1998)] leading to very accurate analytical potentials well adapted to perform
reaction dynamics studies. Overall, the topographies of both PESs are in good
agreement with the benchmark potentials of Rogers et al., but those presented
in this work reproduce better the height and degeneracy of the two states at
the saddle point. Moreover, the long range potential in the entrance channel
does not require any cutoff. These features makes the new PESs particularly
suitable for a comparison of the dynamics on each of them. The new set of PESs
were then used to perform quantum mechanics and quasiclassical trajectory
calculations to determine integral and differential cross sections, which are
compared to the experimental measurements by Garton et al. [J. Chem. Phys.,
118, 1585 (2003)].
