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III.G.1.a.

Comparison of levels of theory for Li-C


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 1.8103
2
PM3 1.8561
2
PM6 1.9862
2
composite G2 1.9503
2
G3 1.9503
2
G3B3 1.9372
2
G4 1.9280
2
CBS-Q 1.9486
2

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) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
hartree fock HF 1.8851
2
1.9586
2
1.9586
2
1.9514
2
1.9503
2
1.9499
2
1.9558
2
1.9325
2
1.9317
2
1.9354
2
1.9451
2
1.9614
2
1.9327
2
1.9322
2
1.9539
2
1.9338
2
1.9328
2
ROHF   1.9161
1
1.9161
1
1.9073
1
1.9000
1
1.9000
1
1.9071
1
1.8781
1
1.8781
1
  1.8929
1
1.9163
1
1.8822
1
1.8808
1
1.9081
1
1.8831
1
1.8816
1
density functional LSDA 1.8943
2
1.9381
2
1.9381
2
1.9237
2
1.9190
2
1.9179
2
1.9260
2
1.9044
2
1.9029
2
1.9025
2
1.8792
1
1.9225
2
1.9020
2
  1.9209
2
1.8680
1
 
SVWN   1.9379
2
    1.9194
2
1.8842
1
1.9262
2
1.8636
1
1.8636
1
1.8699
1
  1.8967
1
1.8671
1
  1.8920
1
1.8680
1
 
BLYP 1.9222
2
1.9643
2
1.9643
2
1.9515
2
1.9507
2
1.9497
2
1.9603
2
1.9377
2
1.9364
2
1.9340
2
1.9053
1
1.9558
2
1.9357
2
       
B1B95 1.8974
2
1.9474
2
1.9474
2
1.9383
2
1.9358
2
1.9351
2
  1.9212
2
1.9195
2
1.9206
2
1.8918
1
1.9451
2
1.9579
1
  1.9430
2
1.8824
1
 
B3LYP 1.9000
2
1.9488
2
1.9488
2
1.9372
2
1.9365
2
1.9357
2
1.9452
2
1.9222
2
1.9204
2
1.9199
2
1.9363
2
1.9432
2
1.9209
2
1.9201
2
1.9437
2
1.9224
2
1.9211
2
B3LYPultrafine         1.9365
2
            1.9080
1
1.8776
1
  1.9060
1
1.9266
2
 
B3PW91 1.9014
2
1.9519
2
1.9519
2
1.9411
2
1.9392
2
1.9385
2
1.9463
2
1.9245
2
1.9226
2
1.9239
2
1.8945
1
1.9487
2
1.9220
2
       
mPW1PW91 1.8967
2
1.9486
2
1.9486
2
1.9382
2
1.9364
2
1.9358
2
1.9439
2
1.9209
2
1.9192
2
1.9212
2
1.8899
1
1.9463
2
1.9187
2
  1.9085
1
1.8800
1
 
M06-2X 1.7708
1
1.9024
1
1.9024
1
1.8939
1
1.9296
2
1.8867
1
1.8974
1
1.8684
1
1.8684
1
1.8757
1
1.8854
1
1.9043
1
1.8732
1
  1.9007
1
1.8741
1
 
PBEPBE 1.9181
2
1.9609
2
1.9609
2
1.9489
2
1.9471
2
1.9461
2
1.9556
2
1.9323
2
1.9305
2
1.9309
2
1.9014
1
1.9543
2
1.9288
2
  1.9208
1
1.8921
1
 
PBEPBEultrafine         1.9081
1
            1.9235
1
1.8901
1
  1.9210
1
1.8918
1
 
PBE1PBE 1.7862
1
1.9129
1
1.9129
1
1.9014
1
1.9350
2
1.8948
1
1.9048
1
1.8733
1
1.8733
1
1.8812
1
1.8882
1
1.9110
1
1.8770
1
  1.9067
1
1.8785
1
 
HSEh1PBE 1.7869
1
1.9129
1
1.9129
1
1.9015
1
1.9354
2
1.8948
1
1.9051
1
1.8741
1
1.8741
1
1.8813
1
1.8891
1
1.9108
1
1.8778
1
  1.9068
1
1.8792
1
 
TPSSh         1.9027
1
  1.9028
1
          1.8999
1
       
Moller Plesset perturbation MP2 1.9091
2
1.9797
2
1.9797
2
1.9745
2
1.9580
2
1.9568
2
1.9646
2
1.9369
2
1.9351
2
1.9376
2
1.9471
2
1.9699
2
1.9394
2
1.8922
1
1.9721
2
1.9435
2
1.8944
1
MP2=FULL 1.9088
2
1.9792
2
1.9792
2
1.9730
2
1.9512
2
1.9499
2
1.9553
2
1.9294
2
1.9274
2
1.9226
2
1.8933
1
1.9608
2
1.9232
2
1.8725
1
1.9288
2
1.8712
1
1.8653
1
ROMP2 1.7800
1
1.9301
1
1.9301
1
1.9247
1
1.9061
1
1.9061
1
1.9175
1
1.8842
1
1.8842
1
1.8957
1
1.8978
1
1.9297
1
1.8953
1
  1.9309
1
   
MP3         1.9544
2
  1.9113
2
                   
MP3=FULL         1.9022
1
  1.9036
1
                   
MP4   1.9857
2
    1.9592
2
      1.9346
2
  1.8958
1
1.9302
1
1.8949
1
  1.9349
1
1.9000
1
 
MP4=FULL   1.9341
1
    1.8967
1
      1.8747
1
    1.9212
1
1.8767
1
  1.8896
1
1.8713
1
 
B2PLYP         1.9896
1
              1.9021
1
       
Configuration interaction CID   1.9784
2
1.9784
2
1.9745
2
1.9520
2
    1.9301
2
                 
CISD   1.9824
2
1.9824
2
1.9785
2
1.9547
2
    1.9316
2
                 
Quadratic configuration interaction QCISD   1.9887
2
1.9887
2
1.9854
2
1.9591
2
1.9583
2
1.9650
2
1.9352
2
1.8819
1
1.8948
1
1.8952
1
1.9718
2
1.8934
1
  1.9324
1
1.8974
1
 
QCISD(T)         1.9076
1
          1.8973
1
1.9320
1
1.8960
1
  1.9359
1
1.9008
1
 
Coupled Cluster CCD   1.9815
2
1.9815
2
1.9781
2
1.9549
2
1.9542
2
1.9617
2
1.9321
2
1.8790
1
1.8925
1
1.8929
1
1.9690
2
1.8915
1
  1.9304
1
1.8955
1
 
CCSD         1.9044
1
          1.8948
1
1.9288
1
1.8930
1
1.8917
1
1.9317
1
1.8970
1
1.8935
1
CCSD=FULL         1.8963
1
          1.8915
1
1.9201
1
1.8750
1
1.8708
1
1.8877
1
1.8692
1
1.8621
1
CCSD(T)         1.9071
1
          1.8970
1
1.9316
1
1.8957
1
1.8947
1
1.9355
1
1.9000
1
1.8979
1
CCSD(T)=FULL         1.8990
1
          1.8935
1
1.9227
1
1.8775
1
1.8739
1
1.8903
1
1.8724
1
1.8652
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 2.0053
2
1.9903
2
1.9267
2
1.9283
2
1.9752
2
1.9692
2
density functional B3LYP 1.9996
2
1.9878
2
1.9340
2
1.9335
2
1.9555
2
1.9542
2
Moller Plesset perturbation MP2 2.0280
2
1.9940
2
1.9482
2
1.9264
2
2.0001
2
1.9878
2
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.