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IV.A.4.b.

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 1.218
G4 1.120
CBS-Q 2.319

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
hartree fock HF 17.819 4.819 4.620 4.920 1.9171 1.420 1.070 1.420 1.820 1.420 1.917 3.520 1.820 1.820 1.720 1.820 2.116
density functional LSDA 17.119 5.220 5.220 4.220 6.420 6.120 5.620 5.320 4.920 6.220     5.720 5.020 5.620   4.916
SVWN   4.720     6.020   5.220                    
BLYP 12.019 3.420 3.520 3.820 2.820 2.720 2.820 2.819 2.820 2.720     2.818 3.317 2.917   3.813
B1B95 14.520 3.720 3.720 2.820 4.220 5.220 3.520 3.520 3.220 4.120     3.620 3.120 4.316   2.916
B3LYP 13.719 3.419 3.220 3.220 2.420 2.220 2.120 2.020 2.020 2.320 2.117 2.120 2.020 2.020 2.120 3.311 2.216
B3LYPultrafine         2.420   3.57             2.317   2.020  
B3PW91 14.220 3.520 3.520 2.720 3.820 3.520 3.020 2.920 2.620 3.420     3.120 2.620 2.717   2.316
mPW1PW91 14.820 3.719 3.920 2.720 3.919 3.619 3.020 3.020 2.920 3.820     3.120 2.620 3.219   2.416
M06-2X         3.320                        
PBEPBE 13.320 3.819 3.720 2.820 4.020 3.720 3.220 3.220 2.920 3.720 2.617   3.519 2.820 3.119 4.810 2.616
PBEPBEultrafine         1.969                        
PBE1PBE         4.120                        
HSEh1PBE         3.920                        
TPSSh         3.818   3.018             2.518      
Moller Plesset perturbation MP2 13.320 4.119 3.920 3.618 2.237 3.119 0.7159 3.119 2.920 3.420   2.120 2.719 1.841 3.311   3.410
MP2=FULL   6.012     2.237 3.318 2.319 3.219 3.120       4.112 3.611      
MP3         2.220   2.018                    
MP3=FULL         2.018   1.915                    
B2PLYP         2.218                 1.016      
B2PLYP=FULLultrafine         1.417                        
Configuration interaction CID         2.519                        
CISD         2.617                        
Quadratic configuration interaction QCISD   4.516     1.818 1.817 1.611 2.711 2.910                
Coupled Cluster CCD         2.416                        
CCSD(T)         4.36                        

Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 4.120 2.920 4.120 1.420 4.720 4.720
density functional B1B95 4.317 6.117        
B3LYP 3.320 3.620 2.920 2.120 3.020 3.020
Moller Plesset perturbation MP2 2.619 4.819 3.117 3.318 3.620 3.620
For descriptions of the methods (AM1, HF, MP2, ...) and basis sets (3-21G, 3-21G*, 6-31G, ...) see the glossary in section I.C. Predefined means the basis set used is determined by the method.