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XVII.C.1.

Calculated Ionization Energy for CO (Carbon monoxide)

Experimental Ionization Energy is 14.014 ± 0.0003 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  
composite G4 14.057
CBS-Q 14.044

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 cc-pV(T+d)Z
hartree fock HF 10.714 12.981 12.981 12.935 12.987 12.987 13.071 13.006 13.006 12.930 13.018 12.991 13.000 12.993 13.030 13.006 12.994 13.000
density functional LSDA 12.592 14.400 14.400 14.449 14.437 14.437 14.618 14.573 14.573 14.416 14.599 14.458 14.576   14.608 14.594   14.576
SVWN   14.400     14.437 14.437 14.618 14.573 14.573 14.416   14.458 14.576   14.608 14.594    
BLYP 11.944 13.654 13.654 13.724 13.708 13.708 13.931 13.841 13.841 13.697 13.900 13.732 13.865         13.865
B1B95 12.360 14.060 14.060 14.084 13.946 14.012 14.156 14.086 14.086 13.974 14.042 14.027 14.010 14.014 14.066 14.028 14.020 14.010
B3LYP 12.313 14.029 14.029 14.078 14.043 14.043 14.221 14.143 14.143 14.017 14.184 14.060 14.154 14.165 14.207 14.177 14.172 14.154
B3LYPultrafine         14.043             14.060 14.154   14.207 14.177    
B3PW91 12.304 14.013 14.013 14.013 13.963 13.963 14.094 14.028 14.028 13.922 14.054 13.972 14.026         14.026
mPW1PW91 12.286 13.970 13.993 13.990 13.911 13.911 14.048 13.970 13.991 13.889 14.029 13.919 13.975   14.041 14.016   13.975
M06-2X 12.348 14.071 14.071 14.095 14.024 14.024 14.161 14.110 14.110 13.993 14.107 14.041 14.108   14.142 14.117    
PBEPBE 12.005 13.722 13.722 13.753 13.716 13.716 13.903 13.816 13.816 13.694 13.871 13.738 13.837 13.852 13.891 13.869 13.863 13.837
PBEPBEultrafine         13.716             13.738 13.837   13.891 13.869    
PBE1PBE 12.212 13.947 13.947 13.953 13.895 13.895 14.034 13.957 13.957 13.855 13.995 13.907 13.965   14.010 13.985    
HSEh1PBE 12.200 13.937 13.937 13.941 13.885 13.885 14.024 13.953 13.953 13.846 13.990 13.896 13.961   14.001 13.980    
TPSSh             13.965                      
Moller Plesset perturbation MP2 11.923 13.755 13.755 13.944 13.974 13.974 14.128 14.032 14.032 14.073 14.056 13.953 14.221 14.304 14.155 14.280 14.332 14.221
MP2=FULL 11.926 13.761 13.761 13.949 13.972 13.972 14.126 14.039 14.039 14.062 14.059 13.957 14.214 14.304 14.158 14.265 14.332 14.214
MP3         13.959   14.087                      
MP3=FULL         13.955   14.084                      
MP4   13.789     14.043       14.115   14.129 14.040 14.297   14.246 14.354    
Configuration interaction CID   13.487 13.487 13.604 13.832     13.884                    
CISD   13.226 13.226 13.287 13.660     13.733                    
Quadratic configuration interaction QCISD   12.995 12.995 13.047 13.544 13.544 13.683 13.658 13.658 13.723 13.652 13.574 13.857   13.747 13.904   13.857
QCISD(T)         13.555           13.664 13.585 13.871   13.776 13.925    
Coupled Cluster CCD   13.539 13.539 13.685 13.953 13.953 14.087 14.020 14.020 14.079 14.018 13.953 14.203   14.135 14.250    
CCSD         13.601           13.700 13.624 13.901 13.971     13.987  
CCSD=FULL         13.600           13.703 13.626 13.901 13.977 13.798 13.944 13.993  
CCSD(T)   13.116     13.608   13.755   13.714   13.715 13.633 13.921 13.997 13.825 13.975 14.017 13.921
CCSD(T)=FULL         13.607           13.717 13.634 13.920 14.001 13.826 13.971 14.021  

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 12.989 13.047 12.901 12.997 12.926 12.920
density functional B3LYP 14.244 14.137 14.155 14.108 14.181 14.156
Moller Plesset perturbation MP2 14.214 14.163 14.155 14.115 14.122 14.121
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.