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Relative enthalpies of isomers - Comparison of 298.15K enthalpies (kJ mol-1)

Isomers of C2H2O3

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a CHOCOOH 298124 oxo acetic acid   sketch of oxo acetic acid
b CHOOCHO 1588674 diformyl ether   sketch of diformyl ether
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1
-363.0 b
PM3 -501.0 a
-393.9 b
PM6
-329.4 b
composite G1 NC
NC
G2MP2 NC
NC
G2 NC
NC
G3 NC
NC
G3B3 NC
NC
G4
NC
CBS-Q NC
NC

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 daug-cc-pVTZ
hartree fock HF NC NC NC NC NC NC NC NC NC NC   NC NC NC NC   NC
density functional LSDA   NC     NC NC NC NC NC NC     NC NC NC    
BLYP NC NC NC NC NC NC NC NC NC NC   NC NC NC      
B1B95 NC NC NC NC NC NC NC NC NC NC   NC NC NC NC    
B3LYP NC NC NC NC NC NC NC NC NC NC   NC NC NC NC NC  
B3LYPultrafine         NC                        
B3PW91 NC NC NC NC NC NC NC NC NC NC   NC NC NC      
mPW1PW91 NC NC NC NC NC NC NC NC NC NC   NC NC NC NC    
M06-2X NC NC NC NC NC NC NC NC NC NC   NC NC NC NC NC  
PBEPBE NC NC NC NC NC NC NC NC NC NC   NC NC NC NC    
HSEh1PBE NC NC NC NC NC NC   NC NC NC   NC NC NC NC NC  
TPSSh         NC   NC     NC       NC      
wB97X-D     NC   NC   NC   NC     NC NC NC   NC  
B97D3   NC     NC   NC   NC   NC NC   NC   NC  
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 daug-cc-pVTZ
Moller Plesset perturbation MP2 NC NC NC NC NC NC NC NC NC NC   NC NC NC NC    
MP2=FULL NC NC NC NC NC NC NC NC NC NC   NC NC NC NC    
MP3         NC                        
MP3=FULL         NC   NC                    
MP4   NC     NC                        
Configuration interaction CID   NC NC NC NC     NC                  
CISD   NC NC NC NC     NC                  
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 daug-cc-pVTZ
Quadratic configuration interaction QCISD   NC NC NC NC NC NC NC NC NC   NC NC NC NC    
Coupled Cluster CCD   NC NC NC NC NC NC NC NC NC   NC NC NC NC NC  
CCSD(T)=FULL         NC               NC        
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 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 NC NC NC NC NC NC     NC
density functional B3LYP NC NC NC NC NC NC     NC
PBEPBE                 NC
Moller Plesset perturbation MP2 NC NC NC NC NC NC     NC
NC = not calculated
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.
gaw refers to the group additivity method implemeted in the NIST Chemistry Webbook.
See section Calculated; Vibrations; Scale Factors; Scale factors to list vibrational scaling factors.
See section Calculated; Vibrations; Scale Factors; Calculate a scale factor to calculate a vibrational scaling factor for a given set of molecules.