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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) TZVP 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  
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  
SVWN   6.668     7.565 7.565 8.052 7.945 7.945 7.764    
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  
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 6.163 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  
PBEPBEultrafine   5.610     6.458 6.458 7.040 6.847     6.590  
PBE1PBE 1.102 6.067 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       6.583      
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
Moller Plesset perturbation MP2 -1.215 3.875   5.013 5.679 5.675 6.368 5.903 5.900 6.245 5.518  
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   5.744  
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) TZVP 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           5.742  
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           5.810  
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) TZVP cc-pVDZ

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 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.