VRC-TST calculations were implemented in the VaReCoF program. The OneDMin code was used for the estimation of Lennard-Jones parameters. Electronic structure calculations using density functional theory were performed in Gaussian09 and Gaussian16, and wavefunction methods were performed in MOLPRO, as well as the MRCC program extension to MOLPRO for the implementation of coupled-cluster theory with higher order excitations for open-shell species and for CCSDTQ(P) and beyond for closed-shell species.