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The barrier height of the F+H2 reaction revisited: Coupled-cluster and multireference configuration-interaction benchmark calculations

2008; American Institute of Physics; Volume: 128; Issue: 3 Linguagem: Inglês

10.1063/1.2822905

1520-9032

Hans‐Joachim Werner, Mihály Kállay, Jürgen Gauß,

Atmospheric Ozone and Climate

Large scale coupled-cluster benchmark calculations have been carried out to determine the barrier height of the F+H2 reaction as accurately as possible. The best estimates for the barrier height of the linear and bent transition states amount to 2.16 and 1.63 kcal/mol, respectively. These values include corrections for core correlation, scalar-relativistic effects, spin-orbit effects, as well as the diagonal Born-Oppenheimer correction. The CCSD(T) basis-set limits are estimated using extrapolation techniques with augmented quintuple and sextuple-zeta basis sets, and remaining N-electron errors are determined using coupled-cluster singles, doubles, triples, quadruples calculations with up to augmented quintuple-zeta basis sets. The remaining uncertainty is estimated to be less than 0.1 kcal/mol. The coupled-cluster results are used to calibrate multireference configuration-interaction calculations with empirical scaling of the correlation energy.