National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 18October 2016
NIST Standard Reference Database 101
IIntroduction
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
VIInput and output files
VIITutorials and Units
VIIILinks to other sites
IXFeedback
XOlder CCCBDB versions
XIIGeometries
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers
XXIOddities

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IV.A.4. (XIV.F.)

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

Isomers of CHO2

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a HOCO 2564865 Hydrocarboxyl radical   sketch of Hydrocarboxyl radical
b HCOO 9000392 formate neutral radical   sketch of formate neutral radical
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1
-108.9 b
PM3
-129.4 b
PM6 -162.5 a
-75.8 b
composite G1 NC
NC
G2MP2 NC
NC
G2
NC
G3
NC
G3B3
NC
G4 NC
CBS-Q
NC

Methods with standard basis sets
STO-3G 6-31G 6-31G* 6-311G* cc-pV(T+d)Z cc-pCVDZ
hartree fock HF         NC  
density functional LSDA NC NC NC NC NC  
BLYP         NC  
B1B95         NC  
B3LYP         NC  
B3PW91         NC  
mPW1PW91         NC  
PBEPBE         NC  
STO-3G 6-31G 6-31G* 6-311G* cc-pV(T+d)Z cc-pCVDZ
Moller Plesset perturbation MP2         NC NC
MP2=FULL         NC NC
STO-3G 6-31G 6-31G* 6-311G* cc-pV(T+d)Z cc-pCVDZ
Quadratic configuration interaction QCISD         NC  
QCISD(T)         NC  
Coupled Cluster CCD         NC  
CCSD(T)         NC  
STO-3G 6-31G 6-31G* 6-311G* cc-pV(T+d)Z cc-pCVDZ
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 III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.