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Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
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III.D.6.a. (XVII.D.)

Calculated Electron Affininty for C2 (Carbon diatomic)

Experimental Electron Affinity is 3.273 ± 0.008 eV
Please note! These calculated electron affinity 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

Electron Affinities in eV
Methods with predefined basis sets
semi-empirical AM1  
PM3  
PM6  
composite G2 3.100
G3 3.155
G3B3 3.164
G4 3.177
CBS-Q 3.172

Electron Affinities 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 cc-pV(T+d)Z
hartree fock HF -0.620 3.740 3.740 3.801 3.764 3.771 4.488 4.218 4.218 3.812 4.466 4.074 4.355 4.459 4.521 4.539 4.541 4.355
density functional LSDA -0.394 3.567 3.567 3.629 3.790 3.624 4.542 7.114 4.201 3.696   3.969 4.351   4.582     4.351
SVWN   3.567     3.624   7.509       4.497              
BLYP -0.991 2.852 2.852 2.916 2.917 2.917 3.933 3.482 3.482 3.007   3.263 3.672         3.672
B1B95 -0.697 3.204 3.204 3.233 3.319 3.215 4.019 3.693 3.693 3.269   3.533 3.933   4.161 4.156   3.933
B3LYP -0.541 3.367 3.367 3.423 3.415 3.415 4.319 3.949 3.949 3.490 4.257 3.748 4.116 4.238 4.352 4.365 4.367 4.116
B3LYPultrafine         3.415                     4.366    
B3PW91 -0.453 3.517 3.517 3.535 3.521 3.521 4.299 4.008 4.008 3.576   3.835 4.138         4.138
mPW1PW91 -0.409 3.596 3.575 3.590 3.595 3.595 4.371 4.068 4.049 3.625   3.904 4.197         4.197
M06-2X     3.451   3.451                          
PBEPBE -0.836 3.079 3.079 3.113 3.723 3.723 6.738 6.369 6.369 6.010   6.069 6.518         3.779
PBE1PBE         3.529                          
HSEh1PBE   2.718     3.512   4.417           3.173          
TPSSh         3.390   4.175     3.437     3.997          
wB97X-D     3.592   3.588       4.083       4.202     4.417    
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 cc-pV(T+d)Z
Moller Plesset perturbation MP2 -2.801 1.744 1.744 1.867 2.101 2.101 2.981 2.660 2.660 2.382 2.910 2.539 2.982 3.154 3.213 3.270 3.292 2.982
MP2=FULL -2.806 1.741 1.741 1.863 2.103 2.103 2.983 2.662 2.663 2.384   2.538 2.985 3.163 3.210   3.300 2.985
MP3         2.959                          
MP3=FULL         2.966   3.787                      
MP4   1.307     1.754       2.307       2.671          
B2PLYP         2.757               3.506          
Configuration interaction CID   2.381 2.381 2.504 2.815     3.371                    
CISD   2.212 2.212 2.335 2.688     3.245                    
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 cc-pV(T+d)Z
Quadratic configuration interaction QCISD   1.586 1.586 1.725 2.166 2.166 3.029 2.747 2.747 2.518   2.601 3.126         3.126
QCISD(T)         1.899             2.351 2.876   3.068 3.179    
Coupled Cluster CCD   1.934 1.934 2.074 2.454 2.454 3.285 3.035 3.035 2.803   2.895 3.406   3.537 3.662    
CCSD         2.247                          
CCSD(T)   1.281     1.908   2.815   2.491     2.362 2.895 3.087 3.082 3.200 3.227 2.895
CCSD(T)=FULL         1.911                 3.096     3.235  
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 cc-pV(T+d)Z

Electron Affinities in eV
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 4.236 4.195 4.328 4.329 4.259 4.265
density functional B3LYP 3.992 3.970 4.085 4.085 3.973 3.965
Moller Plesset perturbation MP2 2.486 2.712 2.563 2.776 2.417 2.419
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.