return to home page Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
You are here: Home > Ions > Energy > Calculated Ionization Energy OR Calculated > Energy > Ion > Calculated Ionization Energy

Calculated Ionization Energy for C2H (Ethynyl radical)

20 09 09 14 00
Experimental Ionization Energy is 11.61 ± 0.07 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
composite G4 11.809

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 daug-cc-pVTZ
hartree fock HF 8.640 10.327 10.327 10.107   9.927 10.024 10.042 10.044 9.880   10.004 10.011 10.012 10.004 10.011 10.011 10.008
density functional LSDA 10.895 12.381 12.381 12.172 12.102 12.110 12.270 12.346 12.343 12.128   12.222 12.341   12.281 12.347    
BLYP   11.452 11.452   11.147                          
B1B95 10.204 11.571 11.570 11.353 11.355 11.263 11.422 11.493 11.428 11.397   11.359 11.434   11.407 11.529    
B3LYP 10.175 11.612 11.612 11.405 11.354 11.351 11.546 11.540 11.539 11.303     11.533 11.556 11.538 11.575 11.559  
B3LYPultrafine         11.354                     11.555    
B3PW91 10.204 11.640 11.640 11.398 11.317 11.296 11.428 11.474 11.477 11.300   11.395 11.472          
mPW1PW91 10.159 11.580 11.602 11.357 11.229 11.221 11.362 11.394 11.419 11.244   11.320 11.397          
M06-2X     11.636                              
PBEPBE   11.611 11.611   11.320 11.321 11.488 11.508 11.520 11.329   11.433 11.534          
PBE1PBE         11.248                          
HSEh1PBE   13.419     14.497               13.725          
TPSSh         14.504               14.583          
wB97X-D     11.606   11.240   11.367   11.416   11.426 11.367 11.391     11.398    
B97D3                         11.417          
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 daug-cc-pVTZ
Moller Plesset perturbation MP2 9.102 10.973 10.973 10.747 13.583 10.941 11.088 13.797 11.200 11.153   11.086 11.388   11.188 11.425 11.494  
MP2=FULL 9.103 10.976 10.976 10.750 10.934 10.957 11.104 11.183 11.217 11.181   11.097 11.430     11.469 11.532  
MP3         10.799                          
MP3=FULL         13.741   13.905                      
MP4   10.990     10.918       11.197       13.855          
B2PLYP                         14.408          
Configuration interaction CID   10.846 10.846 10.622 10.695     10.903                    
CISD   10.899 10.899 10.675 10.737     10.935                    
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 daug-cc-pVTZ
Quadratic configuration interaction QCISD   11.117 11.117 10.909 10.987 11.009 11.129 11.188 11.215 11.190   11.141 11.372          
QCISD(T)         11.062             11.223 11.500          
Coupled Cluster CCD     10.936 10.715 10.814 10.835 10.966 11.034 11.064 11.024   10.969 11.229   11.060 11.259    
CCSD(T)         11.055             11.223 11.483     11.515    
CCSD(T)=FULL         11.071                          
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 daug-cc-pVTZ

Ionization Energies in eV
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD cc-pVTZ-PP aug-cc-pVTZ-PP Def2TZVPP
hartree fock HF 10.039 9.850 10.151 9.976 10.205 10.207     10.013
density functional B3LYP 11.225 11.034 11.434 11.392 11.552 11.532     11.546
Moller Plesset perturbation MP2 10.559 10.748 10.812 11.009 10.865 10.871     11.393
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.