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Calculated Ionization Energy for I2 (Iodine diatomic)

Experimental Ionization Energy is 9.3074 ± 0.0002 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 AM1  
PM3  

Ionization Energies in eV
Methods with standard basis sets
3-21G 3-21G*
hartree fock HF 9.611 8.973
density functional B3LYP 9.598 9.252
B3PW91 9.715 9.333
mPW1PW91 9.749 9.344
PBEPBE 9.377 9.063
wB97X-D   9.357
B97D3 9.333  
3-21G 3-21G*
Moller Plesset perturbation MP2 9.104 9.156
MP2=FULL 9.096 9.149
MP4 9.138  
Configuration interaction CID 9.256 9.144
CISD 9.240 9.128
3-21G 3-21G*
Quadratic configuration interaction QCISD 9.209 9.156
Coupled Cluster CCD 9.230 9.183
3-21G 3-21G*

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 9.724   9.724   9.837 9.808
density functional B3LYP 9.873   9.873   9.942 9.966
Moller Plesset perturbation MP2 9.297   9.297   9.337 9.334
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.