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Calculated Ionization Energy for Si2 (Silicon diatomic)

20 09 09 14 00
Experimental Ionization Energy is 7.9 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  
composite G4 8.424

Ionization Energies in eV
Methods with standard basis sets
3-21G 3-21G* 6-31G* 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVTZ daug-cc-pVTZ
hartree fock HF     7.304           8.886       8.873
density functional BLYP     7.884                    
B3LYP                 9.119        
B3LYPultrafine                       8.354  
M06-2X   9.186 9.137                    
PBE1PBE     9.267                    
HSEh1PBE 9.405     8.382             8.367    
TPSSh     8.175 8.167     8.007       7.998    
wB97X-D   9.366 9.283 9.281   9.262     9.236 9.281 9.205 9.205  
B97D3 8.235   8.114 8.117   8.122   8.068 8.071   8.058 8.044  
3-21G 3-21G* 6-31G* 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVTZ daug-cc-pVTZ
Moller Plesset perturbation MP2     8.151   8.122       8.789        
MP3=FULL     8.790 8.085                  
B2PLYP     8.931               8.301    
3-21G 3-21G* 6-31G* 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVTZ 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                 8.864
density functional B3LYP                 8.343
PBEPBE                 8.059
Moller Plesset perturbation MP2                 8.944
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.