For computational feasibility, the cc-pVDZ basis set was used in the direct potential evaluations. Higher accuracy is obtained by accounting for limitations in (i) the CASPT2 method, (ii) the small cc-pVDZ basis set, and (iii) fragment geometry relaxation effects, through the development of orientation-independent one-dimensional correction terms. These correction term evaluations are based on explicit calculations for R1, as a function of the radical-radical separation distance, R CC . To correct for method and basis set limitations, a fully-relaxed minimum energy path (MEP) for 2 CF 3 --→ ←--C 2 F 6 was constructed in D 3dsymmetry using the explicitly-correlated CASPT2-F12 method with the aug-cc-pVTZ-F12 basis set. Single-point energies along this fully-relaxed MEP were obtained using explicitlycorrelated and Davidson-corrected multireference configuration interaction with the same basis set, MRCI-F12+Q/aug-cc-pVTZ-F12. Additionally, a so-called "spin-splitting" approach was also used, taking advantage of the use of high-accuracy single-reference methods to describe the energy of the triplet state along the MEP. The energy of the triplet state was evaluated using explicitly-correlated coupled-cluster theory with single and double excitations and perturbative connected triples, employing a restricted spin Hartree-Fock reference wavefunction, RHF-UCCSD(T)-F12b, along with an aug-cc-pVTZ-F12 basis. Then, the energy of the singlet state was obtained by calculating singlet-triplet energy gaps using both of the high-accuracy multireference methods considered, CASPT2-F12/aug-cc-pVTZ-F12 and MRCI-F12+Q/aug-cc-pVTZ-F12. These spin-splitting-based values are expected to be less sensitive to the multireference method used for singlet-triplet gaps. An average of the two spin-splitting approaches is used as the final reference energy in determining the correction potential.