To gauge the appropriateness of a CASPT2/cc-pVDZ potential for the VRC-TST calculations, various potential corrections as described in Section 2.1.1 were benchmarked against the chosen standard of the average of spin-splitting approaches with singlet-triplet gaps obtained with both MRCI-F12+Q/aug-cc-pVTZ-F12 and CASPT2-F12/aug-cc-pVTZ-F12. In the shorter range, it is expected that the more rigorous and expensive configuration interaction (CI) energies are more accurate. However, in the long range, the lack of size consistency in truncated CI implementations indicates that the CASPT2 potential may be more accurate.