National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 19April 2018
NIST Standard Reference Database 101
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XIXIndex of properties
XXH-bond dimers
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XVII.C.1. (III.D.6.)

Calculated Ionization Energy for CH3CO (Acetyl radical)

Experimental Ionization Energy is 7 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 6.964
G3 7.006
G3B3 6.984
G4 7.032
CBS-Q 7.013

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) 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ
hartree fock HF 5.105 6.511 6.511 6.887 6.539 6.521 6.645 6.510 6.493 6.371     6.499 6.451 6.486 6.565 6.515
density functional LSDA 5.642 7.020 7.020 7.392 7.235 7.228 7.489 7.336 7.322 7.129       7.223 7.346 7.456  
BLYP 5.371 6.558 6.558 6.935 6.767 6.758 7.054 6.876 6.865 6.658       6.761 6.897    
B1B95 5.481 6.695 6.695 7.027 6.740 6.799 7.000 6.966 6.837 6.679       6.768 6.766 6.868  
B3LYP 5.629 6.844 6.844 7.217   7.000 7.242 7.080 7.066 6.884   7.155 7.110 6.983 7.084 7.196 7.135
B3LYPultrafine         7.011                       7.134
B3PW91 5.643 6.903 6.903 7.226 7.020 7.008 7.197 7.058 7.044 6.890       6.977 7.045    
mPW1PW91 5.640 6.876 6.911 7.233 6.986 6.973 7.167 7.020 7.036 6.885       6.942 7.009    
M06-2X     6.864   8.414                        
PBEPBE 5.386 6.667     6.834 6.823 7.082 6.917 6.904 6.724     6.963 6.820 6.933    
PBE1PBE         8.527                        
HSEh1PBE   8.647     8.525   8.712               8.595    
TPSSh         8.461   8.643     6.842         8.532    
wB97X-D     6.856           6.986               7.002
B97D3   6.757     6.867   7.077   6.920   6.972       6.926   6.981
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 Def2TZVPP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ
Moller Plesset perturbation MP2   5.843 5.843 6.239 6.363 6.409 6.631 6.414 6.466 6.410     6.668 6.397 6.645 6.681  
MP2=FULL   5.842 5.842 6.237 6.349 6.395 6.618 6.406 6.458         6.390 6.606    
MP3         6.584                        
MP3=FULL         8.082   8.316                    
MP4   5.923     6.424                        
B2PLYP         8.225                   6.892    
Configuration interaction CID   6.235 6.235 6.651 6.547     6.564                  
CISD   6.238 6.238 6.656 6.548     6.566                  
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 Def2TZVPP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ
Quadratic configuration interaction QCISD   6.259 6.259 6.695 6.579 6.628 6.839 6.627           6.616      
QCISD(T)         6.545                 6.588 -52.875    
Coupled Cluster CCD   6.188 6.188 6.611 6.558 6.609 6.806 6.599           6.592      
CCSD         6.579                        
CCSD(T)         6.544                 6.587 6.836    
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 Def2TZVPP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ

Ionization Energies in eV
Methods with effective core potentials (select basis sets)
daug-cc-pVDZ daug-cc-pVTZ daug-cc-pVQZ Sadlej_pVTZ CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF         7.100 6.696 7.056 6.651 6.982 6.981
density functional B3LYP         7.551 7.273 7.536 7.276 7.369 7.361
Moller Plesset perturbation MP2         6.452 6.571 6.447 6.572 6.310 6.306
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.