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XVII.C.1.

Calculated Ionization Energy for C2H4 (Ethylene)

Experimental Ionization Energy is 10.5138 ± 0.0006 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 CBS-Q 10.537
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 aug-cc-pVDZ aug-cc-pVTZ
hartree fock HF 7.383 8.896 8.896 8.739 8.646 8.643 8.747 8.726 8.733 8.611 8.771 8.702 8.738 8.720 8.746
density functional BLYP 8.873 10.008 10.008 9.929 9.893 9.900 10.078 10.096 10.106 9.906   10.006 10.134    
B1B95 9.102 10.205 10.205 9.682 10.061 10.077 10.197 10.205 10.210 10.080   10.152 10.205 10.188  
B3LYP 9.014 10.206 10.206 10.106 10.064 10.069 10.219 10.238 10.248 10.072 10.293 10.163 10.272 10.241 10.285
B3LYPultrafine         10.064                    
B3PW91 9.084 10.271 10.271 10.143 10.099 10.104 10.216 10.236 10.244 10.099   10.174 10.254    
mPW1PW91 9.030 10.213 10.237 10.105 10.033 10.037 10.154 10.165 10.196 10.054   10.110 10.186    
M06-2X         10.049                    
PBEPBE 9.049 10.195 10.195 10.099 10.061 10.063 10.211 10.223 10.228 10.064   10.153 10.250    
Moller Plesset perturbation MP2FC 8.243 9.933 9.933 9.840 9.944 10.025 10.167 10.140 10.246 10.205 10.247 10.165 10.436 10.306 10.494
MP2FU   9.935     9.958 10.039 10.179 10.154 10.259     10.175      
MP3         9.803                    
MP4         9.952                    
B2PLYP             10.139                
Configuration interaction CID         9.625     9.769              
CISD         9.643                    
Quadratic configuration interaction QCISD   9.934     9.863 9.936 10.052 10.017 10.109     10.042 10.250    
QCISD(T)         9.957                    
Coupled Cluster CCD         9.821   10.011 9.978       10.008 10.218    
CCSD(T)         9.956                    
CCSD(T)=FULL                         10.420 10.284  
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 8.620 8.520 8.759 8.682 8.819 8.823
density functional B3LYP 9.935 9.876 10.088 10.051 10.181 10.175
Moller Plesset perturbation MP2FC 9.687 9.813 9.898 10.017 9.938 9.944
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.