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III.G.1.a.

Comparison of levels of theory for K-K


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 PM3 3.1495
1
PM6 2.8084
1
composite G2 4.1633
1
G3 4.1634
1
G3B3 4.0213
1
CBS-Q 4.1632
1

average calculated bond lengths (Å)
Methods with standard basis sets
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP
hartree fock HF 3.4636
1
4.2209
1
4.2245
1
4.1921
1
4.2040
1
4.2040
1
4.2044
1
4.1977
1
4.1977
1
4.2011
1
4.2012
1
4.1874
1
density functional LSDA 3.4052
1
2.9085
1
2.9085
1
3.8128
1
3.8298
1
3.8298
1
3.8298
1
3.8221
1
3.8221
1
3.8236
1
  3.8393
1
SVWN   3.8600
1
    3.8298
1
3.8298
1
3.8298
1
3.8221
1
3.8221
1
3.8236
1
   
BLYP 3.5070
1
4.0072
1
3.9839
1
3.9777
1
3.9960
1
3.9960
1
3.9959
1
3.9916
1
3.9916
1
3.9949
1
  4.0059
1
B1B95 3.4395
1
3.9864
1
3.9864
1
3.9536
1
3.9700
1
3.9700
1
3.9698
1
3.9742
1
3.9742
1
3.9720
1
  3.9753
1
B3LYP 3.4743
1
3.9883
1
3.9639
1
3.9563
1
3.9719
1
3.9719
1
3.9718
1
3.9692
1
3.9692
1
3.9707
1
  3.9773
1
B3LYPultrafine         3.9706
1
             
B3PW91 3.4665
1
4.0666
1
4.0647
1
4.0100
1
4.0232
1
4.0232
1
4.0232
1
4.0221
1
4.0221
1
4.0232
1
  4.0264
1
mPW1PW91 3.4583
1
4.0676
1
4.0655
1
4.0123
1
4.0257
1
4.0257
1
4.0256
1
4.0250
1
4.0250
1
4.0253
1
  4.0270
1
M06-2X 3.4102
1
3.8311
1
3.7603
1
3.8042
1
3.8129
1
3.8129
1
3.8121
1
3.8175
1
3.8175
1
3.8147
1
  3.8175
1
PBEPBE 3.4822
1
4.0323
1
4.0218
1
3.9877
1
4.0046
1
4.0046
1
4.0044
1
4.0016
1
4.0016
1
4.0033
1
  4.0109
1
PBEPBEultrafine         4.0020
1
             
PBE1PBE 3.4562
1
4.0398
1
4.0398
1
3.9993
1
4.0133
1
4.0133
1
4.0132
1
4.0119
1
4.0119
1
4.0123
1
  4.0130
1
HSEh1PBE 3.4573
1
4.0508
1
4.0447
1
4.0062
1
4.0173
1
4.0173
1
4.0172
1
4.0143
1
4.0143
1
4.0162
1
  4.0201
1
TPSSh         4.0915
1
  4.0915
1
         
Moller Plesset perturbation MP2 3.4846
1
4.2265
1
4.2044
1
4.1989
1
4.0665
1
4.0665
1
4.0629
1
3.9194
1
3.9194
1
4.0008
1
  4.1843
1
MP2=FULL 3.4701
1
4.2210
1
4.1564
1
4.1990
1
4.0664
1
4.0664
1
4.0628
1
3.9139
1
3.9139
1
4.0002
1
  4.1460
1
MP3         4.0569
1
  4.0752
1
         
MP3=FULL         4.0752
1
  4.0730
1
         
MP4   4.2175
1
    4.0652
1
      3.9448
1
    4.1668
1
MP4=FULL   4.2123
1
    4.0651
1
      3.9406
1
     
Configuration interaction CID   4.2195
1
4.1865
1
4.1989
1
4.0659
1
    3.9986
1
       
CISD   4.2434
1
4.1926
1
4.2227
1
4.0791
1
    3.9985
1
       
Quadratic configuration interaction QCISD   4.2435
1
4.1927
1
4.2247
1
4.0965
1
4.0965
1
4.0928
1
3.9886
1
3.9886
1
4.0434
1
  4.1916
1
QCISD(T)         4.1099
1
    3.9955
1
      4.1912
1
Coupled Cluster CCD   4.2196
1
4.1864
1
4.2000
1
4.0691
1
4.0691
1
4.0660
1
3.9655
1
3.9655
1
4.0321
1
  4.1636
1
CCSD         4.0968
1
    3.9886
1
      4.1916
1
CCSD=FULL         4.0967
1
            4.1661
1
CCSD(T)         4.1112
1
    3.9967
1
      4.1912
1
CCSD(T)=FULL         4.1111
1
            4.1700
1

average calculated bond lengths (Å)
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 4.3781
1
  4.3781
1
  4.1952
1
4.1955
1
density functional B3LYP 4.3241
1
  4.3241
1
  3.9752
1
3.9679
1
Moller Plesset perturbation MP2 4.4255
1
  4.4255
1
  4.2129
1
4.1908
1
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.