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XVII.C.1.

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 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) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ
hartree fock HF 9.600 12.199 12.199 12.122 11.984 11.984 12.038 12.076 12.076 11.911 12.102 11.982 12.019 11.972 12.020
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  
SVWN   13.624         13.657                
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  
B3LYP 11.422 12.952 12.952 12.942 12.835 12.835 12.984 13.024 13.024 12.819 13.059   13.015 12.977 13.032
B3LYPultrafine         12.835                    
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         13.232                    
PBEPBE 11.240 12.791 12.791 12.751 12.652 12.652 12.801 12.820 12.820 12.632   12.675 12.819    
PBE1PBE         12.892                    
HSEh1PBE         12.874                    
TPSSh             12.809                
Moller Plesset perturbation MP2 12.628 13.876 13.876 14.023 14.091 14.091 14.223 14.247 14.247 14.284 14.247 14.172   14.356  
MP2=FULL   13.877     14.095 14.095 14.227 14.256 14.256     14.176      
MP3         13.214                    
MP3=FULL         13.222   13.317                
B2PLYP         13.027               13.248    
Configuration interaction CID         13.010                    
CISD         12.906                    
Quadratic configuration interaction QCISD         12.843 12.843 12.940 12.982 12.982            
Coupled Cluster CCD         13.343                    
CCSD         12.897                    

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 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 14.181 14.145 14.196 14.195 14.226 14.229
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.