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Comparison of tautomer energies

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rms differences (kJ/mol)
The small italic numers are the number of tautomer pairs with completed calculations.
Methods with predefined basis sets
composite G1 1.512
G2MP2 1.612
G2 1.512
G3 1.220
G3B3 0.918
G3MP2 1.414
G4 2360722.320
CBS-Q 2.220

Methods with standard basis sets
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z daug-cc-pVTZ
hartree fock HF 18.418 4.718 4.519 5.119 2.719 1.519 1.819 1.519 1.819 1.419 2.214 3.719 1.919 1.819 1.719 1.819 2.712 1.919
density functional LSDA 11.57 5.112 4.49 4.48 7.611 7.112 6.612 6.912 6.012 7.112     6.812 5.912 6.512   5.87  
BLYP 12.718 3.619 3.619 4.019 2.919 2.819 2.919 2.919 2.919 2.918     2.917 3.516 2.716   4.79  
B1B95 15.219 3.818 3.719 3.119 4.519 6.419 3.719 4.419 3.419 4.319     3.819 3.319 4.515 5.510 3.012  
B3LYP 14.318 3.318 3.219 3.419 2.519 2.419 2.219 2.119 2.119 2.418 2.313 2.219 2.119 2.119 2.219 2.119 2.612  
B3LYPultrafine         2.519   3.37             2.118   2.119    
B3PW91 14.819 3.319 3.419 2.719 3.919 3.719 3.219 3.019 2.719 3.818     3.219 2.719 3.016 5.16 2.412  
mPW1PW91 15.419 3.318 3.719 2.719 4.118 3.818 3.219 3.119 3.019 4.118     3.319 2.819 3.419   2.612  
M06-2X     3.019   3.319         5.89 3.315     4.29   4.29    
PBEPBE 14.019 3.818 3.719 2.919 4.219 3.919 3.419 3.419 3.019 4.118 2.618   3.519 3.019 3.419 4.312 2.912  
PBEPBEultrafine         4.219                          
PBE1PBE         4.319                          
HSEh1PBE   3.219     4.319   3.419             3.019        
TPSSh         4.017   3.217     3.714       2.717        
wB97X-D     3.318   3.918   3.018   2.618     2.318 2.918 2.518   2.518    
B97D3   3.318     2.818   2.618   2.418   2.419 2.519   2.518   2.518   4.415
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z daug-cc-pVTZ
Moller Plesset perturbation MP2 13.819 4.518 4.219 4.318 3.119 3.019 2.219 3.119 3.119 3.519   2.219 2.819 2.916 3.112 4.010 4.17  
MP2=FULL   6.312     3.219 3.119 2.219 3.319 3.219 7.59     4.212 3.811   4.99    
MP3         2.319   2.717                      
MP3=FULL         2.117   1.816                      
B2PLYP         2.417         2.47       1.115   1.37    
B2PLYP=FULLultrafine         1.822               1.816 1.516   3.116    
Configuration interaction CID         2.518                          
CISD         2.716                          
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z daug-cc-pVTZ
Quadratic configuration interaction QCISD   4.810     1.817 1.817 1.414 2.612 2.313 4.19       2.79   2.89    
Coupled Cluster CCD         2.217                          
CCSD         3.39         4.26       2.89   2.56    
CCSD=FULL         2.97         5.66                
CCSD(T)         2.99                          
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z daug-cc-pVTZ

Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD cc-pVTZ-PP aug-cc-pVTZ-PP Def2TZVPP
hartree fock HF 4.219 3.019 4.219 1.419 4.819 4.819     2.018
density functional B1B95 3.713 6.513              
B3LYP 3.419 3.819 3.019 2.319 3.019 3.019     2.318
PBEPBE                 3.118
Moller Plesset perturbation MP2 2.818 4.819 3.317 3.318 3.919 3.919     2.718
For descriptions of the methods (AM1, HF, MP2, ...) and basis sets (3-21G, 3-21G*, 6-31G, ...) see the glossary in section Resources; Glossary. Predefined means the basis set used is determined by the method.