A recently developed strategy for the computation at
affordable
cost of reliable barrier heights ruling reactions in the gas phase
(junChS, [Barone, V.;J. Chem. Theory Comput.2021,17,4913−492834228935]) has been extended to the employment of explicitly correlated (F12)
methods. A thorough benchmark based on a wide range of prototypical
reactions shows that the new model (referred to as junChS-F12), which
employs cost-effective revDSD-PBEP86-D3(BJ) reference geometries,
has an improved performance with respect to its conventional counterpart
and outperforms the most well-known model chemistries without the
need of any empirical parameter and at an affordable computational
cost. Several benchmarks show that revDSD-PBEP86-D3(BJ) structures
and force fields provide zero point energies and thermal contributions,
which can be confidently used, together with junChS-F12 electronic
energies, for obtaining accurate reaction rates in the framework of
the master equation approach based on the ab initio transition-state
theory.