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Calculated Ionization Energy for C2N2 (Cyanogen)

Experimental Ionization Energy is 13.37 ± 0.01 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  
PM6  
composite G2 13.352
G3 13.361
G3B3 13.394
G4 13.403
CBS-Q 13.269

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) 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
hartree fock HF   12.199 12.199 12.122 11.984 11.984 12.038 12.076 12.076 11.911   12.102 12.029 11.982 12.019   11.972 12.020 12.026
density functional LSDA 12.012 13.624 13.624 13.604 13.514 13.514 13.657 13.734 13.734 13.506       13.537 13.713   13.652 13.725  
BLYP 10.995 12.531 12.531 12.537 12.440 12.440 12.632 12.658 12.658 12.435       12.470 12.662        
B1B95 11.510 12.983 12.983 12.944 12.705 12.839 12.950 12.977 12.977 12.819       12.858 12.822   12.794 12.836  
B3LYP 11.422 12.952 12.952 12.942 12.835 12.835 12.984 13.024 13.024 12.819   13.059 13.028   13.015 13.037 12.977 13.032 13.039
B3LYPultrafine         12.835                         13.032  
B3PW91 11.538 13.094 13.094 13.024 12.917 12.917 13.016 13.061 13.061 12.885       12.932 13.033        
mPW1PW91 11.547 13.063 13.101 13.026 12.879 12.879 12.982 13.015 13.050 12.879       12.893 12.991        
M06-2X     13.359   13.232                            
PBEPBE 11.240 12.791 12.791 12.751 12.652 12.652 12.801 12.820 12.820 12.632     12.835 12.675 12.819        
PBE1PBE         12.892                            
HSEh1PBE   13.052     12.874   12.980               12.999        
TPSSh         12.705   12.809     12.667         12.827        
wB97X-D     13.204   13.004   13.100   13.141     13.143   13.345 13.089     13.099  
B97D3   12.762     12.591   12.721   12.739   12.755       12.727     12.752  
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
Moller Plesset perturbation MP2   13.876 13.876   14.091 14.091 14.223 14.247 14.247 14.284   14.247 14.474 14.172     14.356    
MP2=FULL   13.877 13.877   14.095 14.095 14.227 14.256 14.256 14.294       14.176          
MP3         13.214                            
MP3=FULL         13.222   13.317                        
MP4   13.267     13.470       13.669                    
B2PLYP         13.027                   13.248        
Configuration interaction CID   12.976 12.976 13.025 13.010     13.147                      
CISD   12.851 12.851 12.873 12.906     13.044                      
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
Quadratic configuration interaction QCISD         12.843 12.843 12.940 12.982 12.982         12.880          
QCISD(T)         12.842                 12.885     13.034    
Coupled Cluster CCD   13.234 13.234 13.338 13.343 13.343 13.442 13.482 13.482         13.396     13.532    
CCSD         12.897                            
CCSD(T)                           12.928     13.079    
CCSD(T)=FULL         12.897                            
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP Def2TZVPP 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)
daug-cc-pVDZ daug-cc-pVTZ daug-cc-pVQZ Sadlej_pVTZ CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF         12.153 11.913 12.132 12.039 12.152 12.151
density functional B3LYP         12.953 12.755 12.930 12.849 13.047 13.030
Moller Plesset perturbation MP2           14.145   14.195    
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.