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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 Si2 (Silicon diatomic)

Experimental Electron Affinity is 2.202 ± 0.01 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 2.245
G3 2.271
G4 2.251
CBS-Q 2.263

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
hartree fock HF -5.953 0.730 0.459 0.720 0.982 0.983 1.186 1.070 1.070 0.850 0.990 0.794 0.307 0.454 0.482 1.061 1.059
density functional LSDA -3.588 6.552 2.606 2.692 2.609 2.609 2.827 2.780 2.780 2.555   2.471 2.617   2.745    
SVWN   2.654         2.824       2.692            
BLYP -4.257 1.746 1.601 1.777 1.710 1.624 1.911 1.814 1.866 1.579   1.485 1.647        
B1B95 -4.242 5.373 1.812 1.891 1.810 1.795 1.971 1.889 1.889 1.811   1.649 1.850   1.886    
B3LYP -4.381 1.940 1.735 1.864 1.751 1.893 2.144 2.026 1.917 1.837 1.974 1.765 1.730 1.873 1.901 1.936 2.096
B3LYPultrafine         1.751                     1.935  
B3PW91 -4.256 2.095 1.896 2.002 2.013 2.013 2.042 1.996 2.103 1.939   1.731 1.978        
mPW1PW91 -5.444 2.077 1.866 1.980 1.994 1.880 2.013 2.106 2.079 1.758   1.696 1.947        
M06-2X     1.930   1.930                        
PBEPBE -3.967 2.031 1.913 2.034 1.964 1.913 2.186 2.047 2.073 1.843   1.768 1.951        
PBE1PBE         1.986                        
HSEh1PBE   2.045     1.971   2.157           1.928        
TPSSh         1.998   2.164     1.918     1.951        
wB97X-D     1.966   1.980       2.068       1.931     2.101  
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
Moller Plesset perturbation MP2 -5.090 1.865 1.705 1.905 1.566 1.694 1.942 1.635 1.797 1.952 1.814 1.722 2.012 2.227 2.134 2.287 2.324
MP2=FULL   1.867 1.716 1.908 1.769 1.694 1.941 1.794 1.794     1.726 2.034 2.241      
MP3         1.470                        
MP3=FULL         1.468   1.732                    
MP4   1.698     1.686               1.978        
B2PLYP         1.806               1.786        
Configuration interaction CID   1.318 1.195 1.425 1.370     1.469                  
CISD   1.316 1.232 1.462 1.384                        
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
Quadratic configuration interaction QCISD   1.434 1.452 1.684 1.499   1.760 1.629 1.633     1.519 1.644        
QCISD(T)         1.587             1.584 1.944   2.064    
Coupled Cluster CCD     1.374 1.608 1.421   1.723 1.593       1.486 1.566   1.680    
CCSD         1.514                        
CCSD(T)                       1.563 1.937   2.059    
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

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 0.988 0.364 1.057 0.855 1.009 0.639
density functional B3LYP 1.908 1.794 1.958 1.848 1.921 1.792
Moller Plesset perturbation MP2 1.537 1.640 1.684 1.707 1.496 1.782
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.