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You are here: Calculated > Geometry > Calculated geometry > One type of bond

Comparison of levels of theory for I-I


Click on an entry for a histogram of the values.
The subscript refers to how many bonds of that type have been calculated.
average calculated bond lengths (Å)
Methods with predefined basis sets
semi-empirical AM1 2.5166
2
PM3 2.6593
2
PM6 2.5967
3

average calculated bond lengths (Å)
Methods with standard basis sets
STO-3G 3-21G 3-21G* 6-31G* 6-311G*
hartree fock HF 2.8461
3
2.9789
4
2.8103
4
  2.6486
2
ROHF   3.0028
3
2.8483
3
  2.5955
1
density functional LSDA 2.7124
1
2.6033
1
2.6033
1
  2.6118
1
BLYP 2.9678
3
3.0597
4
2.8776
4
  2.7339
2
B1B95 2.8791
3
2.8279
3
2.8279
3
  2.6503
2
B3LYP 2.9227
3
3.0145
4
2.8395
4
  2.6943
2
B3LYPultrafine   3.0515
3
    2.6518
1
B3PW91 2.9019
3
2.9851
4
2.8064
4
  2.6650
2
mPW1PW91 2.8889
3
2.9735
4
2.7966
4
  2.6561
2
M06-2X 2.8664
3
2.9865
3
2.7867
4
  2.6000
1
PBEPBE 2.9270
3
3.0125
4
2.8245
4
  2.6888
2
PBEPBEultrafine   3.0493
3
    2.6511
1
PBE1PBE 2.8838
3
2.8306
3
2.8306
3
  2.6127
1
HSEh1PBE 2.8889
3
3.0179
3
2.8405
3
  2.6213
1
TPSSh 3.0095
2
3.0297
3
2.8503
3
  2.6293
1
wB97X-D 2.9642
2
3.1065
2
2.7988
4
  2.6101
1
B97D3 3.0656
2
3.0344
4
3.0177
2
  2.6666
1
STO-3G 3-21G 3-21G* 6-31G* 6-311G*
Moller Plesset perturbation MP2 2.8900
3
3.0347
4
2.8230
4
2.7361
1
2.6887
2
MP2=FULL 2.8900
3
3.0350
4
2.8211
4
  2.6811
2
ROMP2 2.8900
3
2.8604
3
2.8605
3
  2.6416
1
MP3         2.6898
2
MP3=FULL         2.6523
1
MP4   2.9285
2
    2.7005
2
MP4=FULL   2.9095
1
    2.6644
1
B2PLYP 2.9060
3
3.0595
3
2.8702
3
  2.6475
1
B2PLYP=FULL 2.9060
3
3.0595
3
2.8696
3
  2.6485
1
B2PLYP=FULLultrafine 2.9986
2
3.1582
2
2.9849
2
  2.6485
1
Configuration interaction CID   3.0300
4
2.8224
4
  2.6648
2
CISD   3.0353
4
2.8232
4
  2.6659
2
STO-3G 3-21G 3-21G* 6-31G* 6-311G*
Quadratic configuration interaction QCISD   3.0488
4
2.8366
4
  2.6890
2
QCISD(T)         2.7018
2
QCISD(T)=FULL         2.6622
1
Coupled Cluster CCD   3.0403
4
2.8334
4
  2.6854
2
CCSD         2.6437
1
CCSD=FULL         2.6452
1
CCSD(T)         2.7015
2
CCSD(T)=FULL         2.7040
2
STO-3G 3-21G 3-21G* 6-31G* 6-311G*

average calculated bond lengths (Å)
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 2.8902
4
  2.8902
4
  2.9276
4
2.9200
4
2.7883
4
  2.7845
4
ROHF             2.7885
4
  2.7848
4
density functional LSDA             2.7641
4
  2.6057
2
BLYP             2.8725
4
  2.8667
4
B1B95             2.7795
4
  2.7743
4
B3LYP 2.9438
4
  2.9438
4
  2.9800
4
2.9720
4
2.8284
4
  2.8227
4
B3LYPultrafine             2.8284
4
  2.8227
4
B3PW91             2.7936
4
  2.7878
4
mPW1PW91             2.7829
4
  2.7773
4
M06-2X             2.7680
4
  2.7640
4
PBEPBE             2.8174
4
  2.8114
4
PBEPBEultrafine             2.8839
3
  2.8114
4
PBE1PBE             2.7797
4
  2.7743
4
HSEh1PBE             2.7900
4
  2.7845
4
TPSSh             2.8005
4
  2.7954
4
wB97X-D 3.0418
2
  3.0418
2
  3.0745
2
3.0665
2
2.7862
4
  2.7813
4
B97D3             2.8487
4
  2.8424
4
Moller Plesset perturbation MP2 2.9663
4
  2.9663
4
  2.9997
4
2.9969
4
2.7711
4
  2.7608
4
MP2=FULL             2.7696
4
  2.7571
4
ROMP2             2.7717
4
  2.7614
4
MP3             2.7919
4
  2.6310
2
MP3=FULL             2.7909
4
  2.6295
2
MP4             2.7970
4
  2.6343
2
MP4=FULL             2.7952
4
  2.6315
2
B2PLYP             2.8061
4
  2.8001
4
B2PLYP=FULL             2.8054
4
  2.7991
4
B2PLYP=FULLultrafine             2.8054
4
  2.7991
4
Configuration interaction CID             2.7736
4
  2.7609
4
CISD             2.7743
4
  2.7614
4
Quadratic configuration interaction QCISD             2.7900
4
  2.7852
4
QCISD(T)             2.7997
4
  2.7969
4
QCISD(T)=FULL             2.8625
3
  2.7927
4
Coupled Cluster CCD             2.7860
4
  2.7801
4
CCSD             2.7895
4
  2.7843
4
CCSD=FULL             2.7878
4
  2.7805
4
CCSD(T)             2.7996
4
  2.7965
4
CCSD(T)=FULL             2.7978
4
  2.7924
4
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.