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

Isomers of CH3O2

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a CH3OO 2143580 methylperoxy radical   sketch of methylperoxy radical
b CH2OOH 9000344 CH2OOH   sketch of CH2OOH
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1 71.3 a
PM3 117.5 a
PM6 94.5 a
32.5 b
composite G1 NC
NC
G2MP2 NC
NC
G2 NC
NC
G3 NC
NC
G3B3 NC
NC
G3MP2 NC
G4 NC
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) cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
hartree fock HF                               NC
ROHF NC NC NC NC NC NC NC NC NC NC   NC NC NC NC NC
density functional LSDA NC     NC NC     NC               NC
BLYP                               NC
B3LYP                               NC
B3PW91                               NC
mPW1PW91                               NC
PBEPBE                               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) cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
Moller Plesset perturbation MP2                               NC
MP2=FULL                               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) cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
Quadratic configuration interaction QCISD                       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) cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z

Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
density functional B1B95   NC        

Single point energy calculations (select basis sets)
6-311+G(3df,2p) cc-pVDZ cc-pVTZ aug-cc-pVDZ cc-pV(T+d)Z
Moller Plesset perturbation MP2FC// HF/6-31G* NC   NC   NC
MP2FC// B3LYP/6-31G* NC NC NC   NC
MP2FC// MP2FC/6-31G*     NC NC NC
MP4// HF/6-31G*         NC
MP4// B3LYP/6-31G*         NC
MP4// MP2/6-31G*         NC
Coupled Cluster CCSD// B3LYP/6-31G* NC        
CCSD(T)//B3LYP/6-31G(2df,p)     NC   NC
CCSD// MP2FC/6-31G*       NC  
CCSD(T)// MP2FC/6-31G*       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.