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XVII.C.1.

Calculated Ionization Energy for C3 (carbon trimer)

Experimental Ionization Energy is 13 ± 0.1 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 11.812
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
hartree fock HF 10.453 12.658   12.491 12.538   12.689 12.708 12.708 12.536 12.721 12.671 12.692 12.696 12.706 12.698
density functional LSDA 10.192 12.124 12.124 11.968 12.073 12.073 12.296 12.327 12.327 12.118   12.239 12.330   12.316  
SVWN   12.135     12.073   12.296                  
BLYP 9.577 11.405   11.263 11.349 11.349 11.611 11.592 11.592 11.403   11.523 11.617      
B1B95 10.427 12.237 12.237 12.066 12.047 12.129 12.317 12.321 12.321 12.153   12.274 12.227   12.102  
B3LYP 9.615 12.920   12.262 12.208   12.407 12.393 12.393 12.243 12.419 12.354 12.404   12.399 12.421
B3LYPultrafine         12.208                      
B3PW91 10.417 12.249   12.040 12.103   12.273 12.285 12.285 12.118   12.240 12.277      
mPW1PW91 10.331 12.216 12.245 12.046 12.093   12.273 12.274 12.302 12.137   12.229 12.267      
M06-2X         12.386                      
PBEPBE 9.669 11.539 11.539 11.363 11.446 11.446 11.669 11.653 11.652 11.479   11.601 11.673      
HSEh1PBE         12.056                      
Moller Plesset perturbation MP2FC 8.086 10.684   10.489 10.816   11.037 11.074 11.073 11.058 11.097 11.020 11.262   11.166  
MP2FU   10.686   10.490 10.822   11.042 11.083 11.082     11.023 11.277      
MP3         12.013                      
MP4         17.051               17.623      
B2PLYP         11.575   11.789                  
Configuration interaction CID   11.489   11.359 11.892     12.317                
CISD   11.372   11.237 11.795     12.210                
Quadratic configuration interaction QCISD   10.955   10.818 11.466 11.466 11.660 11.724       11.706 11.949      
QCISD(T)         13.693                      
Coupled Cluster CCD   11.242   11.109 11.726   12.091 12.179       12.106 12.234      
CCSD         11.593                      
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 12.576 12.628 12.585 12.674 12.640 12.637
density functional B3LYP 12.199 12.230 12.220 12.282 12.440 12.427
Moller Plesset perturbation MP2FC 10.658 10.970 10.714 11.027 10.665 10.666
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.