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Calculated Ionization Energy for C2H5 (Ethyl radical)

Experimental Ionization Energy is 8.117 ± 0.008 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  
composite G2 8.116
G3 8.212
G4 8.199
CBS-Q 8.188

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
hartree fock HF 7.299 8.218 8.218 8.139 7.861 7.786 7.837 7.852 7.792 7.716 7.800 7.761 7.765 7.768 7.766 7.767 7.769
density functional LSDA 7.314 8.540 8.540 8.503 8.314 8.278 8.423 8.457 8.420 8.238   8.326 8.411   8.408    
SVWN                     8.439            
BLYP 7.120 8.061 8.061 8.036 7.889 7.849 8.018 8.044 8.006 7.820   7.908 8.012        
B1B95 7.209 8.188 8.188 8.130 7.909 7.861 7.971 8.181 7.944 7.813   7.879 7.929   7.932    
B3LYP 7.427 8.358 8.358 8.319 8.140 8.093 8.224 8.251 8.209 8.053 8.231 8.131 8.204 8.214 8.202 8.215 8.219
B3LYPultrafine         8.140                        
B3PW91 7.473 8.444 8.444 8.389 8.188 8.140 8.238 8.258 8.215 8.095   8.155 8.202        
mPW1PW91 7.491 8.443 8.469 8.404 8.170 8.118 8.218 8.234 8.214 8.096   8.133 8.177        
M06-2X     8.063   8.063                        
PBEPBE 7.176 8.222 8.222 8.180 8.004 7.959 8.102 8.115 8.073 7.922   7.999 8.076        
PBE1PBE         8.148                        
TPSSh         8.137   8.187     8.041     8.152        
wB97X-D     8.377   8.090   8.141   8.116   8.126 8.141 8.086     8.095  
B97D3   8.226     8.019       8.073             8.094  
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
Moller Plesset perturbation MP2 6.625 8.004 8.004 7.971 7.748 7.781 7.884 7.863 7.915 7.815 7.902 7.858 7.995   7.962    
MP2=FULL 6.623 8.004     7.746 7.782 7.885 7.865 7.915     7.859          
MP3         7.811                        
MP3=FULL         7.811   7.956                    
MP4         7.768                        
B2PLYP                         8.078        
Configuration interaction CID         7.840     7.931                  
CISD         7.833                        
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
Quadratic configuration interaction QCISD   8.088     7.844 7.886 7.983 7.957       7.965          
QCISD(T)         7.798                        
Coupled Cluster CCD         7.853     7.962       7.970          
CCSD         7.849                        
CCSD(T)         7.800               8.070        
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

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 8.137 7.840 8.143 7.847 8.208 8.211
density functional B3LYP 8.374 8.189 8.441 8.256 8.404 8.401
Moller Plesset perturbation MP2 8.026 7.802 8.026 7.821 8.068 8.065
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.