To assess how well our cost effective method performs against computational reference data, we investigated the CF 2 dimer (see Figure ). This diffusion controlled reaction has previously been studied by Truhlar et al. using using multifaceted variable-reactioncoordinate variational transition-state theory (VRC-VTST) with system-specific quantum Rice-Ramsperger-Kassel theory (SS-QRRK). To compare with their data, we calculated the dissociation barrier at 800K (see Figure ) using IBSI as the quantum chemical descriptor. depending on γ cleave , while the barrier resulting from SS-QRRK at this temperature was reported to be at 268.78 kJ mol -1 . Hence, for a cutoff value γ cleave = 0.10 we get an almost perfect match to the reference barrier, showing the accuracy of our method given the right choice for the cutoff threshold. We repeated this for several higher temperatures and compared these values to the reference values obtained with SS-QRRK (see Supporting Information Figure ). While our method is able to predict the barriers quite well over a wide temperature range, it fails to mimic the increase in barrier height for temperatures above roughly 1200K (see Supporting Information Figure ). However, this could potentially be attributed to a breakdown in the RRHO model. Nevertheless, this example shows that our cost efficient methodology compared well to computational benchmarks.