Geometry Comparison
I2 (Iodine diatomic)
distance is atom 1 () to atom 2 ()
Experimental bond length is 2.665 Å
original data displayed. press to display differences
differences displayed. press to display original data
Calculated bond length in Å
Methods with predefined basis sets
| semi-empirical |
AM1 |
2.538 |
| PM3 |
2.668 |
Calculated bond length in Å
Methods with standard basis sets
|
|
3-21G |
3-21G* |
6-311G* |
| hartree fock |
HF |
2.865 |
2.696 |
2.703 |
| density functional |
BLYP |
2.938 |
2.750 |
2.775 |
| B1B95 |
|
|
2.694 |
| B3LYP |
2.902 |
2.719 |
2.737 |
| B3PW91 |
2.877 |
2.691 |
2.706 |
| mPW1PW91 |
2.868 |
2.684 |
2.698 |
| PBEPBE |
2.901 |
2.706 |
2.726 |
| Moller Plesset perturbation |
MP2FC |
2.918 |
2.711 |
2.714 |
| MP2FU |
2.918 |
2.709 |
2.718 |
| MP3 |
|
|
2.731 |
| MP4 |
2.948 |
|
2.739 |
| Configuration interaction |
CID |
2.938 |
2.715 |
2.712 |
| CISD |
2.942 |
2.716 |
2.713 |
| Quadratic configuration interaction |
QCISD |
2.954 |
2.727 |
2.733 |
| QCISD(T) |
|
|
2.744 |
| Coupled Cluster |
CCD |
2.949 |
2.725 |
2.730 |
| CCSD(T) |
|
|
2.744 |
| CCSD(T)=FULL |
|
|
2.746 |
Calculated bond length in Å
Methods with effective core potentials (select basis sets)
|
|
CEP-31G |
CEP-31G* |
CEP-121G |
CEP-121G* |
LANL2DZ |
SDD |
| hartree fock |
HF |
2.770 |
|
2.770 |
|
2.817 |
2.805 |
| density functional |
B3LYP |
2.823 |
|
2.823 |
|
2.863 |
2.853 |
| Moller Plesset perturbation |
MP2FC |
2.836 |
|
2.836 |
|
2.877 |
2.868 |
Values that are outliers may reflect different atom numbering for
different levels of theory.
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