National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 18October 2016
NIST Standard Reference Database 101
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XIXIndex of properties
XXH-bond dimers
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XVII.C.1. (III.D.6.)

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 AM1  
PM3  
composite G2 10.533
G3 10.516
G3MP2 10.557
G4 10.429
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 cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
hartree fock HF 7.382 8.896 8.896 8.739 8.647 8.643 8.747 8.726 8.733 8.611 8.770 8.702 8.738 8.749 8.720 8.746 8.751
density functional LSDA 9.751 11.068 11.068 10.963 10.935 10.953 11.096 11.145 11.165 10.970   11.049 11.186 11.200 11.128 11.195 11.203
SVWN   11.068     10.935   11.096       11.186            
BLYP 8.860 10.059 10.059 9.966 9.917 9.934 10.116 10.130 10.152 9.947   10.054 10.186        
B1B95 9.085 10.240 10.240 10.128 10.069 10.093 10.214 10.396 10.232 10.098   10.177 10.229 10.243 10.188 10.240 10.246
B3LYP 8.991 10.221 10.221 10.110 10.057 10.069 10.221 10.236 10.255 10.075 10.293 10.171 10.281 10.295 10.248 10.294 10.300
B3LYPultrafine         10.057                     10.294  
B3PW91 9.061 10.291 10.291 10.149 10.094 10.106 10.219 10.234 10.251 10.103   10.182 10.264        
mPW1PW91 9.007 10.225 10.249 10.105 10.022 10.032 10.151 10.157 10.196 10.050   10.111 10.189        
M06-2X     10.049   10.049                        
PBEPBE 9.047 10.267 10.267 10.155 10.102 10.116 10.267 10.272 10.292 10.121   10.219 10.319 10.334     10.340
PBE1PBE         10.040                        
HSEh1PBE   11.520     11.332   11.453           11.484        
TPSSh         9.960   10.089     9.966     10.131        
wB97X-D     10.242   10.038   10.166   10.201   10.218 10.166 10.195     10.205  
B97D3   10.156     9.983       10.167             10.200  
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 8.243 9.909 9.909 9.817 9.935 10.017 10.153 10.128 10.230 10.192 10.247 10.155 10.419 10.503 10.293 10.465 10.526
MP2=FULL 8.245 9.906 9.906 9.817 9.946 10.028 10.163 10.140 10.242 10.210   10.163 10.445 10.528 10.316 10.523 10.552
MP3         9.803   10.046                    
MP3=FULL         9.814   10.022                    
MP4   9.951     9.934       10.217       10.402        
B2PLYP         9.963   10.139           10.258        
B2PLYP=FULL   10.074     9.967   10.142                    
Configuration interaction CID   9.721 9.721 9.609 9.625     9.769                  
CISD     9.737 9.622 9.642     9.785                  
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   9.916 9.916 9.811 9.841 9.914 10.029 9.995 10.087 10.039   10.021 10.250        
QCISD(T)         9.935             10.126 10.372   10.255 10.416  
Coupled Cluster CCD   9.891 9.891 9.787 9.821 9.897 10.011 9.978 10.072 10.029   10.008 10.218   10.122 10.242  
CCSD         9.832                        
CCSD(T)         9.933             10.125 10.370   10.254 10.414  
CCSD(T)=FULL         9.945               10.420   10.284    
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 8.620 8.520 8.759 8.682 8.819 8.823
density functional B3LYP 9.913 9.850 10.073 10.031 10.178 10.172
Moller Plesset perturbation MP2 9.687 9.813 9.874 10.017 9.913 9.917
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.