∆Escf = -1.801

∆Eccsd = 1.180

∆E(T) = 0.662

∆Ecv = -0.041

∆Erel = 0.003

∆Edboc = 0.002

∆Eisomer,elec = 0.005

∆Hisomer,0K = -0.107

∆Hisomer,298K = -0.057

For evaluation of the DFT functionals we obtain a nonrelativistic, all-electron, vibrationless CCSD(T)/CBS energy of 0.0001 kcal/mol at the W2-F12 level. The DFT functionals that were considered in the paper perform reasonably well for this reaction, with isomerization energies ranging between -1.10 (LC-wPBE) and +0.74 (B2K-PLYP). We note that 76% of the fuctionals give isomerization energies (in absolute value) ≤ 0.5 kcal/mol, and 11 functionals give isomerization energies (in absolute value) ≤ 0.1 kcal/mol. Specifically, -0.10 (B3LYP), -0.10 (M05-2X), -0.07 (M06-HF), -0.07 (B98), -0.02 (B97-1), +0.02 (M11-L), +0.02 (t-HCTHh), +0.05 (DSD-PBEP86), +0.05 (t-HCTH), +0.07 (B3PW91-D3), and +0.10 (TPSSh) kcal/mol.

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