National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
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XIXIndex of properties
XXH-bond dimers
XXIOddities

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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) TZVP cc-pVDZ cc-pVTZ cc-pVQZ 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 6.551 6.451 6.747 6.497 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  
SVWN   8.801     8.765   9.017       7.404          
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 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     6.905   8.414                      
PBEPBE 5.386 6.667     6.834 6.823 7.082 6.917 6.904 6.724   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   6.974       6.986       6.962     7.002
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
Moller Plesset perturbation MP2   5.843 5.843 6.239 6.363 6.409 6.631 6.414 6.466 6.410 6.545 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) TZVP cc-pVDZ cc-pVTZ cc-pVQZ 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) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ

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 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.