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Calculated Ionization Energy for HOCO (Hydrocarboxyl radical)

Experimental Ionization Energy is 8.2 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 PM6  
composite G2 7.970
G3 8.005
G3B3 8.015
G4 8.064
CBS-Q 8.012

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   7.818 7.818 8.242 7.716 7.693 7.831 7.640     7.715 7.604 7.610 7.647 7.742 7.654
ROHF         7.607                      
density functional LSDA 6.402 8.080 8.080 8.545 8.317 8.302 8.632 8.381 8.385 8.157   8.279 8.425   8.589  
SVWN   8.059     8.290   8.567       8.464          
BLYP   7.660 7.660 8.087 7.841 7.822 8.159 7.908       7.800 7.941      
B1B95   7.943 7.943 8.334 8.001 7.980 8.212 8.008       7.935 8.006   8.149  
B3LYP   7.949 7.949 8.369 8.082 8.062 8.339 8.108   7.884 8.228 8.026 8.123 8.201 8.285 8.200
B3LYPultrafine         8.082                     8.200
B3PW91   8.000 8.000 8.367 8.081 8.061 8.280 8.085       8.021 8.078      
mPW1PW91   8.019 8.019 8.383 8.086 8.064 8.286 8.080       8.022 8.074      
M06-2X     7.979   7.979                      
PBEPBE   7.760 7.760 8.136 7.895 7.876 8.169 7.942       7.856 7.967      
PBE1PBE         8.034                      
HSEh1PBE   7.951     7.461   7.668           8.036      
TPSSh         8.033   8.237     7.835     8.044      
wB97X-D     7.934   8.024   8.217   7.995   8.074 8.217 7.966     8.024
B97D3   7.859     7.925       7.944             8.031
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   7.026 7.026 7.494 7.465 7.477 7.987 7.421     7.602 7.397 7.669   7.768 7.796
MP2=FULL   7.024 7.024 7.491 7.447 7.459 7.717 7.410       7.390 7.626      
MP3         7.724                      
MP3=FULL         7.706   7.934                  
MP4   7.082     7.513                      
B2PLYP         7.832               7.924      
Configuration interaction CID   7.450 7.450 7.935 7.695     7.627                
CISD   7.449 7.449 7.937 7.691     7.625                
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   7.422 7.422 7.939 7.724 7.731 7.981 7.681       7.651 7.901      
QCISD(T)         7.660             7.599 7.877   7.983  
Coupled Cluster CCD   7.392 7.392 7.887 7.699 7.706 7.935 7.647       7.616 7.861      
CCSD         7.725                      
CCSD(T)                       7.600 7.878   7.981  
CCSD(T)=FULL         7.643                      
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 8.434   8.413   8.238 8.237
density functional B3LYP 8.739   8.719   8.480 8.470
Moller Plesset perturbation MP2 7.744   7.737   7.540 7.537
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.