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

Geometry Comparison

IBr (Iodine monobromide)


distance is atom 1 () to atom 2 ()

Experimental bond length is 2.469  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*
hartree fock HF 2.641 2.477 2.492
density functional LSDA 2.637 2.454 2.484
BLYP 2.711 2.527 2.568
B1B95 2.645 2.464 2.490
B3LYP 2.679 2.499 2.532
B3LYPultrafine 2.679 2.500 2.532
B3PW91 2.658 2.477 2.504
mPW1PW91 2.650 2.470 2.496
M06-2X 2.646 2.475 2.493
PBEPBE 2.680 2.491 2.526
PBEPBEultrafine 2.680 2.492 2.526
PBE1PBE 2.649 2.468 2.493
HSEh1PBE 2.655 2.473 2.501
Moller Plesset perturbation MP2 2.690 2.490 2.504
MP2=FULL 2.691 2.489 2.507
MP4 2.717 2.508 2.527
Configuration interaction CID 2.706 2.494 2.500
CISD 2.710 2.495 2.501
Quadratic configuration interaction QCISD 2.722 2.505 2.522
QCISD(T) 2.726 2.511 2.531
Coupled Cluster CCD 2.716 2.503 2.518
CCSD 2.722 2.505 2.521
CCSD(T) 2.726 2.511 2.531
CCSD(T)=FULL 2.727 2.510 2.533

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 2.576   2.576   2.629 2.595
density functional LSDA 2.616   2.616   2.660 2.630
BLYP 2.664   2.664   2.709 2.678
B1B95 2.605   2.605   2.651 2.619
B3LYP 2.630   2.630   2.677 2.645
B3LYPultrafine 2.630   2.630   2.677 2.645
B3PW91 2.609   2.609   2.656 2.623
mPW1PW91 2.600   2.600   2.648 2.614
M06-2X 2.596   2.596   2.642 2.612
PBEPBE 2.631   2.631   2.676 2.645
PBEPBEultrafine 2.631   2.631   2.676 2.645
PBE1PBE 2.598   2.598   2.646 2.612
HSEh1PBE 2.602   2.602   2.650 2.617
Moller Plesset perturbation MP2 2.644   2.644   2.686 2.658
MP2=FULL 2.644   2.644   2.686 2.658
MP4 2.677   2.677   2.724 2.696
Configuration interaction CID 2.669   2.669   2.717 2.689
CISD 2.674   2.674   2.723 2.694
Quadratic configuration interaction QCISD 2.682   2.682   2.731 2.703
QCISD(T) 2.686   2.686   2.735 2.707
Coupled Cluster CCD 2.676   2.676   2.724 2.696
CCSD 2.682   2.682   2.731 2.702
CCSD(T) 2.686   2.686   2.735 2.707
CCSD(T)=FULL 2.686   2.686   2.735 2.707
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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