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IV.D.1. (XII.C.1.)

Geometry Comparison

HI (Hydrogen iodide)


distance is atom 1 () to atom 2 ()

Experimental bond length is 1.609  Å

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Calculated bond length in Å
Methods with predefined basis sets

Calculated bond length in Å
Methods with standard basis sets
3-21G 3-21G* 6-311G* 6-311G**
hartree fock HF 1.638 1.631 1.624 1.609
density functional BLYP 1.677 1.660 1.654 1.639
B1B95 1.653 1.639 1.632 1.618
B3LYP 1.662 1.647 1.641 1.626
B3PW91 1.657 1.642 1.637 1.623
mPW1PW91 1.654 1.640 1.634 1.620
PBEPBE 1.671 1.654 1.649 1.634
Moller Plesset perturbation MP2 1.657 1.645 1.636 1.606
MP2=FULL 1.657 1.645 1.638 1.607
Configuration interaction CID 1.670 1.651 1.640 1.607
CISD 1.672 1.652 1.641 1.607
Quadratic configuration interaction QCISD 1.674 1.656 1.648 1.612
QCISD(T) 1.674 1.658 1.651 1.613
Coupled Cluster CCD 1.672 1.655 1.647 1.611
CCSD(T) 1.674 1.658 1.651 1.613

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 1.616   1.613   1.615 1.617
density functional B1B95 1.641   1.639   1.638 1.641
B3LYP 1.640   1.638   1.636 1.639
Moller Plesset perturbation MP2 1.637   1.634   1.633 1.637
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
Please use the error report form to report problems.