State-specific rates of H2CO(S)→H2+CO at energies near the top of barrier: A violation of RRKM theory?

Abstract
Unimolecular dissociation rates have been determined for two rovibrational eigenstates in the H2CO X̃ 1A1 electronic ground state. The two levels investigated are separated in energy by ∼30 cm1 at a total energy near 28 300 cm1, which is near the top of the barrier for dissociation to H2+CO. The angular momentum is J=2 for both levels, and they have the same vibration‐rotation symmetry. Contrary to the expectations from conventional RRKM theory, the state higher in energy has a dissociation rate ∼2.5 times slower than the less energetic state.