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Calculated Ionization Energy for KO (Potassium monoxide)

Experimental Ionization Energy is 7.1 ± 0.1 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 PM3  
PM6  
composite G2 6.864
G3 6.807
G3B3 6.800
G4 6.881
CBS-Q 6.107

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
hartree fock HF -1.808 3.022 4.009 3.905 4.227 4.227 4.732 4.431 4.431 4.440   4.363 4.735  
ROHF   3.022 4.009 3.905 4.227 4.227 4.732 4.431 4.431     4.363    
density functional LSDA 4.246 7.393 7.393 7.007 7.565 7.565 8.052 7.945 7.945 7.764   7.728    
BLYP 3.438 5.549 6.367 6.058 6.411 6.411 7.033 6.796 6.796 6.692   6.591    
B1B95 2.788                     6.201    
B3LYP 3.168 5.346 6.272 5.967 6.354 6.354 6.972 6.721 6.721 6.641   6.526 7.039  
B3LYPultrafine   5.345     6.357 6.357 6.975 6.723       6.528    
B3PW91 2.978 5.224 6.116 5.845 6.239 6.239 6.803 6.610 6.610 6.523   6.361    
mPW1PW91 2.844 5.163 6.069 5.784 6.173 6.173 6.729 6.526 6.526 6.451   6.283    
M06-2X 1.021 5.141 6.164 5.808 6.220 6.220 6.768 6.547 6.547 6.483   6.436    
PBEPBE 3.382 5.611 6.413 6.101 6.454 6.454 7.037 6.844 6.844 6.741   6.588 7.128  
PBEPBEultrafine   5.610     6.458 6.458 7.040 6.847       6.590    
PBE1PBE 1.102   6.067 5.769 6.155 6.155 6.723 6.507 6.507 6.440   6.277    
HSEh1PBE 2.864 5.162 6.083 5.775 6.166 6.166   6.523 6.523 6.453   6.293    
TPSSh   5.184 6.033 5.756 6.118 6.118 6.669 6.499   6.398   6.237    
wB97X-D     6.008   6.200   6.797   6.534     6.312   6.797
B97D3   5.599     6.216   6.774   6.583   7.038      
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
Moller Plesset perturbation MP2 -1.215 3.875   5.013 5.679 5.675 6.368 5.903 5.900 6.245   5.518 5.969  
MP2=FULL -1.173 4.031 5.180 5.015 5.681 5.681 6.374 5.913 5.913 6.257   5.806    
ROMP2         5.681 5.681 6.375 5.906 5.906 6.250        
MP3         5.535   6.185         5.308    
MP3=FULL         5.540   6.190         5.612    
MP4   3.986     5.598       5.837          
MP4=FULL   4.137     5.603       5.849          
B2PLYP   4.779 5.746 5.568 6.033 6.033 6.683 6.349 6.349 6.409   6.079    
B2PLYP=FULL 0.532 4.847 5.847 5.569 6.034 6.034 6.685 6.353 6.353 6.413   6.198    
Configuration interaction CID   3.700   4.882 5.424     5.521            
CISD   3.802   4.922 5.445     5.545            
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
Quadratic configuration interaction QCISD   3.924   5.019 5.576 5.576 6.247 5.774 5.774 6.116   5.361    
QCISD(T)         5.591                  
QCISD(T)=FULL         5.596   6.291              
QCISD(TQ)         5.583   6.270              
QCISD(TQ)=FULL         5.589                  
Coupled Cluster CCD   3.738   4.941 5.526 5.526 6.182 5.710 5.710 6.068   5.309    
CCSD         5.557             5.343    
CCSD=FULL         5.562             5.653    
CCSD(T)         5.587                  
CCSD(T)=FULL         5.592             5.718    
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

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         4.243   4.258   4.167 4.171
density functional B3LYP         6.052   6.086   6.225 6.220
Moller Plesset perturbation MP2         5.371   5.473   5.223 5.205
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.