National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
IIntroduction
IIExperimental data
IIICalculated data
IVData comparisons
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XOlder CCCBDB versions
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XIII Vibrations
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XVEntropy data
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XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers
XXIOddities

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XVII.C.1. (III.D.6.)

Calculated Ionization Energy for HCO (Formyl radical)

Experimental Ionization Energy is 8.12 ± 0.04 eV
Please note! These calculated ionizataion energies have the vibrational zero-point energy (zpe) included, but the zpe has NOT been scaled. Click on an entry for more details, including the ionization energy with a scaled zpe.
Original data displayed. Press to display differences.
Differences displayed. Press to display original data.

Ionization Energies in eV
Methods with predefined basis sets
semi-empirical AM1  
PM3  
PM6  
composite G2 8.202
G3 8.263
G4 8.256
CBS-Q 8.264

Ionization Energies in eV
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) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
hartree fock HF 6.449 7.805 7.805 8.093 7.768 7.761 7.872 7.768 7.734 7.668 7.784 7.718 7.754 7.764 7.838 7.785 7.774
ROHF   7.708 7.708   7.637 7.628 7.739 7.628       7.573 7.601        
density functional LSDA 7.141 8.563 8.563 8.821 8.715 8.708 8.909 8.791 8.756 8.648   8.684 8.789   8.884    
SVWN   8.563     8.715   8.909       8.828            
BLYP 6.794 8.029 8.029 8.316 8.197 8.188 8.427 8.268 8.237 8.124   8.175 8.286        
B1B95 6.925 8.203 8.203 8.453 8.197 8.258 8.423 8.350 8.269 8.180   8.228 8.216   8.313    
B3LYP 7.009 8.267 8.267 8.546 8.390 8.381 8.580 8.440 8.407 8.308 8.490 8.359 8.443 8.466 8.552 8.491 8.484
B3LYPultrafine         8.391                     8.491  
B3PW91 7.036 8.331 8.331 8.553 8.399 8.390 8.545 8.435 8.400 8.317   8.364 8.422        
mPW1PW91 7.023 8.300 8.325 8.547 8.361 8.351 8.510 8.395 8.382 8.300   8.328 8.387        
M06-2X     8.183   8.183                        
PBEPBE 6.837 8.150 8.150 8.388 8.271 8.262 8.467 8.332 8.299 8.200   8.251 8.342        
PBE1PBE         8.340                        
HSEh1PBE   8.270     8.339   8.491           8.373        
TPSSh         8.342   8.491     8.262     8.384        
wB97X-D     8.232   8.286       8.278       8.275     8.310  
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
Moller Plesset perturbation MP2   6.968 6.968 7.230 7.548 7.584 7.767 7.599 7.620 7.659 7.678 7.584 7.837   7.851 7.924  
MP2=FULL   6.968     7.542 7.578 7.762 7.598 7.617     7.581          
MP3         7.788                        
MP3=FULL         7.781   7.980                    
MP4         7.609               7.925        
B2PLYP         8.048               8.174        
Configuration interaction CID         7.751     7.778                  
CISD         7.749                        
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
Quadratic configuration interaction QCISD   7.428     7.753 7.789 7.958 7.794 7.818     7.786 8.029        
QCISD(T)         7.729                        
Coupled Cluster CCD         7.745     7.784       7.774          
CCSD         7.760                        
CCSD(T)                       7.766 8.027   8.043 8.116  
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ

Ionization Energies in eV
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 8.264 7.898 8.234 7.849 8.207 8.204
density functional B3LYP 8.846 8.609 8.810 8.580 8.722 8.708
Moller Plesset perturbation MP2 7.387 7.698 7.382 7.684 7.294 7.290
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.