National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 18October 2016
NIST Standard Reference Database 101
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VCost comparisons
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XIII Vibrations
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XIXIndex of properties
XXH-bond dimers
XXIOddities

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III.G.1.a.

Comparison of levels of theory for C-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 1.6768
8
PM3 1.6907
8
PM6 1.8069
17
composite G2 1.8373
13
G3 1.8373
13
G3B3 1.7943
16
G3MP2 1.7184
1
G4 1.7834
17
CBS-Q 1.8376
13

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 aug-cc-pV(T+d)Z cc-pCVTZ
hartree fock HF 1.7921
13
1.8591
13
1.8331
13
1.8598
13
1.8309
14
1.8364
13
1.8369
13
1.8322
13
1.8321
13
1.8297
13
1.8821
5
1.8452
17
1.8430
13
1.8331
13
1.7400
5
1.8432
13
1.8328
13
1.7400
5
1.8562
13
1.7680
3
1.7596
1
ROHF 1.5408
1
1.7062
2
1.6601
2
1.7046
2
1.6590
2
1.6590
2
1.6647
2
1.6588
2
1.6588
2
1.6310
1
  1.6862
1
1.6703
2
1.6602
2
1.6564
2
1.6756
2
1.6632
2
1.6578
2
1.6768
1
1.6776
1
1.7596
1
density functional LSDA 1.7971
13
1.8294
13
1.8130
13
1.8404
13
1.8143
13
1.8138
13
1.8149
13
1.8089
13
1.8094
13
1.8053
13
  1.7760
4
1.8206
13
1.8080
13
1.6661
1
1.8194
13
1.7825
7
1.6671
1
1.7452
3
1.7453
3
1.7127
1
SVWN   1.8463
17
    1.8180
17
1.7757
4
1.8184
17
1.7710
4
1.7713
4
1.7672
4
  1.8121
15
1.7839
4
1.7704
4
  1.7831
4
1.7702
4
  1.8915
1
1.8918
1
1.7127
1
BLYP 1.8239
13
1.8738
13
1.8434
13
1.8753
13
1.7770
17
1.8451
13
1.8469
13
1.8417
13
1.8419
13
1.8369
13
  1.8075
4
1.8510
13
1.8409
13
  1.9071
1
    1.7729
3
1.7735
3
1.7336
1
B1B95 1.7670
9
1.8014
9
1.7917
9
1.8237
9
1.7936
9
1.7935
9
1.8223
13
1.7894
9
1.7898
9
1.7863
9
  1.7820
4
1.7998
9
1.7891
9
1.6703
3
1.8000
9
1.7893
9
1.6709
3
1.7502
3
1.7506
3
1.7105
1
B3LYP 1.8082
13
1.8595
13
1.8289
13
1.8603
13
1.8312
13
1.8306
13
1.8320
13
1.8269
13
1.8223
12
1.8344
16
1.8771
1
1.8380
17
1.8364
13
1.8264
13
1.7212
5
1.8364
13
1.7902
16
1.7216
5
1.8545
13
1.7587
3
1.7152
1
B3LYPultrafine         1.8311
13
            1.7697
3
1.7982
4
1.7862
4
  1.7979
4
1.8182
14
      1.7152
1
B3PW91 1.7987
12
1.8563
13
1.8265
13
1.8565
13
1.8280
13
1.8274
13
1.8282
13
1.8230
13
1.8186
12
1.8201
13
  1.7884
4
1.8330
13
1.8229
13
  1.8893
1
1.8814
2
  1.7551
3
1.7554
3
1.7135
1
mPW1PW91 1.7946
12
1.8531
13
1.8186
12
1.8533
13
1.8249
13
1.8243
13
1.8251
13
1.8199
13
1.8203
13
1.8171
13
  1.7852
4
1.8298
13
1.8199
13
  1.8101
5
1.7796
4
  1.7521
3
1.7525
3
1.7103
1
M06-2X 1.7533
4
1.8062
4
1.7645
17
1.8120
4
1.8260
17
1.7807
4
1.7818
4
1.7778
4
1.7780
4
1.8071
6
  1.7819
4
1.7879
4
1.8104
6
  1.7882
4
1.8103
6
  1.7508
3
1.7511
3
1.7046
1
PBEPBE 1.8098
12
1.8660
13
1.8324
12
1.8619
12
1.8382
13
1.8377
13
1.8388
13
1.8335
13
1.8338
13
1.8304
13
1.8821
1
1.7997
4
1.8434
13
1.8334
13
1.6875
3
1.8366
6
1.8348
7
1.6881
3
1.7669
3
1.7674
3
1.7301
1
PBEPBEultrafine   1.6958
1
    1.8397
7
1.6580
1
1.6593
1
1.6547
1
      1.7781
3
1.8060
4
1.7940
4
  1.8055
4
1.7941
4
      1.7301
1
PBE1PBE 1.7598
4
1.7805
4
1.7805
4
1.8177
4
1.8290
17
1.7841
4
1.7847
4
1.7795
4
1.7797
4
1.7764
4
  1.7857
4
1.7916
4
1.7800
4
  1.7913
4
1.7801
4
  1.9120
1
1.9127
1
1.7114
1
HSEh1PBE 1.7608
4
1.8543
17
1.7807
4
1.8186
4
1.8294
17
1.7843
4
1.8295
17
1.7800
4
1.7802
4
1.7767
4
  1.7862
4
1.7922
4
1.8202
17
  1.7918
4
1.7803
4
  1.7531
3
1.7535
3
1.7118
1
TPSSh   1.8025
3
1.7651
3
1.8043
3
1.7673
16
1.7670
3
1.7673
16
1.7634
3
  1.7649
17
  1.7693
3
1.7764
3
1.7641
16
  1.7765
3
1.7627
3
  1.9149
1
1.9155
1
1.7177
1
wB97X-D     1.7648
17
  1.7656
17
  1.7654
17
  1.7626
17
    1.7663
17
1.7654
17
1.7624
17
    1.7621
17
       
B97D3   1.7897
17
    1.7802
17
      1.7781
17
              1.7774
17
       
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 aug-cc-pV(T+d)Z cc-pCVTZ
Moller Plesset perturbation MP2 1.8143
12
1.8808
13
1.8380
13
1.8841
13
1.7704
17
1.8332
13
1.8339
13
1.7625
17
1.8279
13
1.8216
12
  1.8337
17
1.8437
13
1.8288
13
1.6789
2
1.8468
13
1.8178
8
1.6792
2
1.8499
13
1.7611
3
1.6904
1
MP2=FULL 1.8138
12
1.8803
13
1.8324
12
1.8796
12
1.8312
13
1.8300
13
1.8308
13
1.8263
13
1.8216
12
1.8144
12
  1.7916
4
1.8411
13
1.8209
13
1.6690
2
1.7874
5
1.7777
8
1.6667
2
1.8401
13
1.7477
3
1.6848
1
ROMP2 1.6724
3
1.7390
3
1.7188
3
1.7694
3
1.7170
3
1.7165
3
1.7193
3
1.7143
3
1.7141
3
1.7110
3
  1.7303
1
1.7334
3
1.7164
3
1.7050
1
1.7392
3
1.7175
1
1.7073
1
1.8169
2
1.8182
2
1.7207
1
MP3         1.8289
13
  1.7605
16
        1.7656
3
1.7806
3
1.7571
3
        1.7521
3
1.7529
3
1.6947
1
MP3=FULL         1.7592
16
  1.7578
16
        1.7644
3
1.7787
3
1.7495
3
        1.9020
1
1.8998
1
1.6907
1
MP4   1.8881
11
    1.8459
12
    1.8833
1
1.8171
10
    1.7987
4
1.8120
4
1.7575
6
  1.7965
3
1.6968
2
  1.6904
2
1.6909
2
1.6952
1
MP4=FULL   1.8460
4
    1.7939
4
      1.7881
4
      1.8098
4
1.7828
4
  1.7923
3
1.7596
3
      1.6902
1
B2PLYP 1.7308
3
1.8021
3
1.7616
3
1.8066
3
1.8289
16
1.7653
3
1.7671
3
1.7623
3
1.7626
3
1.8066
5
  1.7680
3
1.7765
3
1.7606
16
  1.7779
3
1.8105
5
  1.7579
3
1.7588
3
1.7035
1
B2PLYP=FULL 1.7307
3
1.8020
3
1.7612
3
1.8065
3
1.7644
3
1.7645
3
1.7663
3
1.7618
3
1.7621
3
1.7558
3
  1.7676
3
1.7759
3
1.7602
3
  1.7768
3
1.7602
3
  1.9121
1
1.9124
1
1.7023
1
Configuration interaction CID   1.8659
12
1.8250
12
1.8690
12
1.8268
13
    1.8217
13
                    1.9102
1
1.9103
1
1.7056
1
CISD   1.8720
12
1.8246
12
1.8669
12
1.8266
13
    1.8169
12
                    1.9102
1
1.9102
1
1.7100
1
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 aug-cc-pV(T+d)Z cc-pCVTZ
Quadratic configuration interaction QCISD 1.8855
2
1.8765
13
1.8297
12
1.8755
12
1.8313
13
1.8256
12
1.8261
12
1.8257
13
1.8346
12
1.8284
11
  1.7942
4
1.8167
9
1.7999
7
  1.8079
4
1.8190
6
  1.7619
3
1.7626
3
1.7195
1
QCISD(T)         1.8246
11
    1.8840
1
      1.7984
4
1.7923
5
1.7730
5
  1.7950
5
1.7547
4
  1.7681
3
1.7693
3
1.7259
1
Coupled Cluster CCD 1.8854
2
1.8744
12
1.8314
12
1.8787
12
1.8322
13
1.8266
12
1.8276
12
1.8267
13
1.8320
11
1.8299
11
  1.7922
4
1.8186
9
1.8027
7
  1.7941
5
1.7845
4
  1.7574
3
1.7581
3
1.7000
1
CCSD         1.8312
13
    1.8820
1
  1.8810
2
  1.7943
4
1.8067
4
1.8190
6
1.6813
2
1.8081
4
1.8132
5
1.6817
2
1.7624
3
1.7632
3
1.7193
1
CCSD=FULL         1.8215
6
        1.8742
2
  1.7928
4
1.8045
4
1.8111
6
1.6726
2
1.7866
3
1.7778
4
1.6706
2
1.9037
1
1.9013
1
1.7147
1
CCSD(T)         1.8462
12
1.8876
1
  1.8838
1
      1.7986
4
1.7832
6
1.7647
6
1.6900
2
1.7863
6
1.7601
4
1.6905
2
1.7682
3
1.7694
3
1.7258
1
CCSD(T)=FULL         1.7858
4
            1.7972
4
1.8092
4
1.7844
4
1.6776
3
1.8093
4
1.6910
2
1.6766
3
1.7587
3
1.6844
2
1.7208
1
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 aug-cc-pV(T+d)Z cc-pCVTZ

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 1.8625
13
1.8410
13
1.8625
13
1.8457
13
1.8402
13
1.8506
13
density functional B1B95 1.9153
7
1.8988
7
1.9157
2
1.8938
2
1.8941
2
1.8973
2
B3LYP 1.8659
13
1.8438
13
1.8663
13
1.8420
13
1.8581
13
1.8512
13
Moller Plesset perturbation MP2 1.8927
13
1.8497
13
1.8877
13
1.8422
13
1.8675
13
1.8750
13
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.