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XVII.C.1.

Calculated Ionization Energy for HCCCN (Cyanoacetylene)

Experimental Ionization Energy is 11.62 ± 0.03 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  
PM6  
composite G2 11.710
G3 11.696
G4 11.694
CBS-Q 11.658

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 8.063 10.203 10.203 9.944 10.000 9.996 10.100 10.141   9.971 10.167 10.040 10.122 10.062 10.127
density functional LSDA 10.432 11.932 11.932 11.820 11.759 11.760 11.928 12.010 12.011 11.776   11.834 12.000 11.944  
SVWN   11.932         11.928                
BLYP 9.476 10.896 10.896 10.809 10.740 10.740 10.958 10.991   10.756   10.826 11.004    
B3LYP 9.829 11.250 11.250 11.147 11.072 11.072 11.251 11.295   11.078 11.326 11.149 11.297 11.263 11.313
B3LYPultrafine         11.072                    
B3PW91 9.935 11.382 11.382 11.229 11.154 11.154 11.281 11.331   11.144   11.214 11.314    
mPW1PW91 9.930 11.380 11.380 11.223 11.145 11.144 11.277 11.313   11.132   11.204 11.300    
M06-2X         11.392                    
PBEPBE 9.705 11.151 11.151 11.026 10.955 10.955 11.129 11.154   10.955   11.027 11.161    
PBE1PBE         11.126                    
HSEh1PBE         11.107                    
TPSSh             11.101                
Moller Plesset perturbation MP2 11.640 12.481 12.481 12.706 12.423 12.442 12.598 12.598   12.600 12.583 12.617   12.798  
MP2=FULL 11.641 12.482 12.482 12.711 12.418 12.438 12.591 12.601   12.572   12.618      
MP3=FULL         11.688   11.835                
B2PLYP         11.199               11.473    
Configuration interaction CID   11.511 11.511 11.528 11.339     11.492              
CISD   11.315 11.315 11.274 11.215     11.379              
Quadratic configuration interaction QCISD   11.169 11.169 11.042 11.133 11.148 11.277 11.320   11.334   11.247 11.505    
QCISD(T)         11.137                    
Coupled Cluster CCD   11.896 11.896 11.995 11.767 11.783 11.911 11.925       11.918      
CCSD         11.135                    
CCSD(T)         11.157                    

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 9.786 9.812 9.973 10.093 9.991 9.995
density functional B3LYP 11.098 10.968 11.204 11.129 11.299 11.288
Moller Plesset perturbation MP2 12.920 12.554 12.971 12.551 13.010 13.016
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.