return to home page

III.G.1.a.

Comparison of levels of theory for F-Si


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 1.6037
2
PM3 1.5801
9
PM6 1.4814
11
composite G2 1.6133
7
G3 1.5928
11
G3B3 1.6126
11
G4 1.5909
12
CBS-Q 1.6007
11

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 cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(T+d)Z
hartree fock HF 1.6147
10
1.6250
11
1.5891
11
1.6749
11
1.5835
21
1.5928
11
1.6007
11
1.5946
11
1.5947
11
1.5789
11
1.5576
6
1.5994
11
1.6343
11
1.5853
11
1.5951
7
1.6191
11
1.5813
11
1.5926
7
1.5537
6
ROHF   1.6518
4
1.6115
4
1.7121
3
1.6192
4
1.6192
4
1.6305
4
1.6240
4
1.6296
3
    1.7104
1
1.6653
4
1.6135
4
1.6067
3
1.6550
3
1.6126
3
1.6038
3
 
density functional LSDA 1.6495
11
1.6207
11
1.5963
11
1.6929
11
1.6060
11
1.6061
11
1.6207
11
1.6119
11
1.6120
11
1.5898
11
  1.7282
1
1.6443
11
1.6074
11
1.6131
2
1.6430
11
1.6293
5
1.6069
2
 
SVWN   1.6458
9
    1.6038
8
1.6905
1
1.6192
9
1.7053
1
1.7053
1
1.6725
1
    1.7368
1
1.7070
1
  1.7371
1
1.6885
1
   
BLYP 1.6736
10
1.6694
11
1.6200
11
1.7180
11
1.6309
11
1.6310
11
1.6496
11
1.6398
11
1.6399
11
1.6156
11
  1.7727
1
1.6688
11
1.6361
11
  1.6441
6
     
B1B95 1.6458
11
1.6221
11
1.5998
11
1.6928
11
1.6076
11
1.6086
11
1.6218
11
1.6136
11
1.6136
11
1.5955
11
  1.7347
1
1.6469
11
1.6079
11
1.6159
2
1.6472
10
1.6317
5
1.6100
2
 
B3LYP 1.6520
11
1.6508
11
1.6051
11
1.6991
11
1.6144
11
1.6144
11
1.6301
11
1.6212
11
1.6507
5
1.5997
11
1.5858
6
1.6326
11
1.6529
11
1.6165
11
1.6290
7
1.6764
7
1.6362
7
1.6262
7
1.5811
6
B3LYPultrafine         1.6143
11
              1.7540
1
1.6698
2
  1.7553
1
1.5998
12
   
B3PW91 1.6751
5
1.6515
11
1.6055
11
1.6988
11
1.6132
11
1.6132
11
1.6266
11
1.6187
11
1.6480
5
1.5991
11
  1.7403
1
1.6520
11
1.6131
11
  1.6220
6
     
mPW1PW91 1.6501
6
1.6471
11
1.6246
5
1.6944
11
1.6094
11
1.6094
11
1.6227
11
1.6144
11
1.6145
11
1.5956
11
  1.7346
1
1.6484
11
1.6315
7
  1.6390
9
1.6398
3
   
M06-2X 1.6679
3
1.6672
3
1.6205
3
1.7235
3
1.6059
11
1.6370
3
1.6530
3
1.6460
3
1.6460
3
1.6243
3
  1.7338
1
1.6795
3
1.6415
3
  1.6742
3
1.6362
3
   
PBEPBE 1.6930
5
1.6676
11
1.6418
5
1.7491
5
1.6274
11
1.6274
11
1.6441
11
1.6344
11
1.6344
11
1.6132
11
1.5992
6
1.7607
1
1.6658
11
1.6302
11
1.6390
2
1.7043
3
1.6530
5
1.6332
2
1.6313
1
PBEPBEultrafine         1.6217
8
              1.7653
1
1.7377
1
  1.7687
1
1.7210
1
   
PBE1PBE 1.7521
1
1.6823
1
1.6823
1
1.7960
1
1.6093
9
1.6997
1
1.7238
1
1.7148
1
1.7148
1
1.6856
1
  1.7346
1
1.7482
1
1.7134
1
  1.7456
1
1.6979
1
   
HSEh1PBE 1.6766
3
1.6789
3
1.6289
3
1.7316
3
1.6102
11
1.6413
3
1.6602
3
1.6507
3
1.6507
3
1.6274
3
  1.7366
1
1.6838
3
1.6458
3
  1.6817
3
1.6408
3
   
TPSSh         1.6509
13
  1.6560
13
            1.6499
13
         
Moller Plesset perturbation MP2 1.6532
5
1.6442
11
1.6022
11
1.7023
11
1.6164
14
1.6175
11
1.6348
13
1.6147
11
1.6145
11
1.6009
10
  1.6297
11
1.6549
11
1.6256
10
1.6272
6
1.6811
7
1.6344
7
1.6262
6
1.5789
6
MP2=FULL 1.6535
5
1.6679
7
1.6234
5
1.7350
5
1.6152
14
1.6162
11
1.6325
11
1.6142
11
1.6423
5
1.6206
5
  1.7462
1
1.6769
7
1.6256
8
1.6207
6
1.6867
4
1.6405
3
1.6189
5
1.5748
6
ROMP2 1.7417
1
1.6835
1
1.6835
1
1.8088
1
1.7116
1
1.7116
1
1.7418
1
1.7163
1
1.7163
1
1.6933
1
  1.7462
1
1.7593
1
1.7173
1
  1.7634
1
     
MP3         1.6115
11
  1.6478
13
                       
MP3=FULL         1.6476
13
  1.6519
13
                       
MP4   1.6793
5
    1.6420
7
    1.6238
2
1.6466
5
    1.7519
1
1.7662
1
1.6138
10
  1.7732
1
1.7149
1
   
MP4=FULL   1.7393
1
    1.7149
1
      1.7205
1
      1.7642
1
1.7172
1
  1.7701
1
1.7062
1
   
B2PLYP         1.6018
8
                1.6628
7
         
B2PLYP=FULLultrafine         1.6125
1
                           
Configuration interaction CID   1.6653
5
1.6196
5
1.7265
5
1.6079
11
    1.6269
7
                     
CISD   1.6684
5
1.6221
5
1.7295
5
1.6092
11
    1.6346
5
                     
Quadratic configuration interaction QCISD   1.6454
11
1.6269
5
1.7377
5
1.6173
11
1.6445
5
1.6564
7
1.6356
7
1.6127
11
1.6256
5
  1.7440
1
1.6798
7
1.6330
6
  1.6897
3
1.6396
3
  1.6079
1
QCISD(T)         1.6396
7
    1.6219
2
      1.7477
1
1.6892
5
1.6397
5
  1.7068
3
1.6547
3
   
Coupled Cluster CCD   1.6677
5
1.6216
5
1.7303
5
1.6135
11
1.6398
5
1.6562
5
1.6311
7
1.6371
5
1.6211
5
  1.7385
1
1.6743
7
1.6320
5
  1.6772
5
1.6280
5
   
CCSD         1.6155
11
    1.6184
2
      1.7414
1
1.6891
3
1.6395
3
1.6904
1
1.7575
1
1.6990
1
1.6838
1
 
CCSD=FULL         1.7112
1
            1.7407
1
1.7603
1
1.7081
1
1.6837
1
1.7548
1
1.6912
1
1.6728
1
 
CCSD(T)   1.6635
1
    1.6135
9
1.6231
2
1.6498
1
1.6212
2
1.6265
1
  1.6225
1
1.7465
1
1.6851
6
1.6356
6
1.6323
3
1.6835
6
1.6347
6
1.6311
3
1.6107
1
CCSD(T)=FULL         1.6436
5
            1.7459
1
1.7631
1
1.6414
3
1.6894
1
1.6898
3
1.6373
3
1.6792
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 1.6973
11
1.6049
11
1.6910
10
1.6058
11
1.6669
11
1.6793
11
density functional B1B95 1.6682
5
1.6004
6
       
B3LYP 1.7179
10
1.6276
10
1.7180
10
1.6310
10
1.6898
10
1.7016
10
Moller Plesset perturbation MP2 1.7346
10
1.6369
10
1.7339
11
1.6404
11
1.7046
11
1.7132
10
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.