National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
IIntroduction
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
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XOlder CCCBDB versions
XIIGeometries
XIII Vibrations
XIVReaction data
XVEntropy data
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XVIIIon data
XVIIIBad calculations
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 1.6653
9
PM3 1.6749
9
PM6 1.8069
17
composite G2 1.8461
14
G3 1.8461
14
G3B3 1.7902
17
G3MP2 1.7184
1
G4 1.7834
17
CBS-Q 1.8311
14

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 1.7908
14
1.8769
14
1.8253
14
1.8598
13
1.8309
14
1.8452
14
1.8458
14
1.8262
14
1.8261
14
1.8231
14
1.8821
5
1.8452
17
1.8371
14
1.8267
14
1.7358
6
1.8373
14
1.8257
14
1.7358
6
1.8562
13
1.7680
3
1.7596
1
ROHF 1.6627
2
1.7678
3
1.7117
3
1.7672
3
1.7100
3
1.7100
3
1.7142
3
1.7087
3
1.7087
3
1.7202
2
  1.6862
1
1.7232
3
1.7123
3
1.7078
3
1.7283
3
1.7144
3
1.7087
3
1.6768
1
1.6776
1
1.7596
1
density functional LSDA 1.8010
14
1.8353
14
1.8152
14
1.8459
14
1.8164
14
1.8159
14
1.8169
14
1.8108
14
1.8112
14
1.8074
14
  1.7760
4
1.8230
14
1.8100
14
1.7482
2
1.8215
14
1.7892
8
1.7487
2
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 1.8276
14
1.8786
14
1.8454
14
1.8805
14
1.7770
17
1.8470
14
1.8487
14
1.8432
14
1.8435
14
1.8387
14
  1.8075
4
1.8532
14
1.8425
14
  1.9071
1
    1.7729
3
1.7735
3
1.7336
1
B1B95 1.7612
10
1.7927
10
1.7839
10
1.8193
10
1.7857
10
1.7856
10
1.8147
14
1.7816
10
1.7819
10
1.7788
10
  1.7820
4
1.7928
10
1.7818
10
1.6801
4
1.7932
10
1.7893
9
1.6806
4
1.7502
3
1.7506
3
1.7105
1
B3LYP 1.8018
14
1.8543
14
1.8214
14
1.8553
14
1.8237
14
1.8231
14
1.8244
14
1.8193
14
1.8145
13
1.8276
17
1.8771
1
1.8380
17
1.8294
14
1.8190
14
1.7205
6
1.8295
14
1.7863
17
1.7208
6
1.8545
13
1.7587
3
1.7152
1
B3LYPultrafine         1.8236
14
            1.7697
3
1.7982
4
1.7862
4
  1.7979
4
1.8182
14
      1.7152
1
B3PW91 1.7919
13
1.8505
14
1.8185
14
1.8508
14
1.8199
14
1.8193
14
1.8200
14
1.8149
14
1.8102
13
1.8122
14
  1.7884
4
1.8254
14
1.8150
14
  1.8893
1
1.8814
2
  1.7551
3
1.7554
3
1.7135
1
mPW1PW91 1.7880
13
1.8474
14
1.8102
13
1.8477
14
1.8167
14
1.8161
14
1.8169
14
1.8117
14
1.8121
14
1.8091
14
  1.7852
4
1.8221
14
1.8120
14
  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 1.8141
13
1.8707
14
1.8348
13
1.8678
13
1.8400
14
1.8394
14
1.8404
14
1.8349
14
1.8353
14
1.8320
14
1.8821
1
1.7997
4
1.8455
14
1.8350
14
1.7283
4
1.8366
6
1.8348
7
1.7287
4
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
      1.7626
17
        1.7624
17
    1.7621
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 1.8293
13
1.8680
14
1.8284
14
1.8702
14
1.7704
17
1.8257
14
1.8243
14
1.7625
17
1.8205
14
1.8135
13
  1.8337
17
1.8371
14
1.8212
14
1.6789
2
1.8401
14
1.8072
9
1.6792
2
1.8499
13
1.7611
3
1.6904
1
MP2=FULL 1.8288
13
1.8676
14
1.8224
13
1.8651
13
1.8237
14
1.8226
14
1.8234
14
1.8174
14
1.8124
13
1.8063
13
  1.7916
4
1.8345
14
1.8133
14
1.6690
2
1.7874
5
1.7777
8
1.6667
2
1.8401
13
1.7477
3
1.6848
1
ROMP2 1.7220
4
1.8002
4
1.7568
4
1.8257
4
1.7554
4
1.7550
4
1.7572
4
1.7521
4
1.7519
4
1.7110
3
  1.7303
1
1.7734
4
1.7552
4
1.7828
2
1.7797
4
1.7952
2
1.7848
2
1.8169
2
1.8182
2
1.7207
1
MP3         1.8222
14
  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   1.8735
12
    1.8351
13
    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   1.8546
13
1.8162
13
1.8565
13
1.8205
14
    1.8154
14
                    1.9102
1
1.9103
1
1.7056
1
CISD   1.8720
12
1.8165
13
1.8669
12
1.8266
13
    1.8081
13
                    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
1.8719
14
1.8261
13
1.8709
13
1.8259
14
1.8203
13
1.8207
13
1.8204
14
1.8283
13
1.8215
12
  1.7942
4
1.8125
10
1.7999
7
  1.8079
4
1.8190
6
  1.7619
3
1.7626
3
1.7195
1
QCISD(T)         1.8220
12
    1.8840
1
      1.7984
4
1.7959
6
1.7676
6
  1.7950
5
1.7547
4
  1.7681
3
1.7693
3
1.7259
1
Coupled Cluster CCD 1.8854
2
1.8624
13
1.8224
13
1.8653
13
1.8255
14
1.8198
13
1.8183
13
1.8200
14
1.8238
12
1.8212
12
  1.7922
4
1.8136
10
1.7939
8
  1.7907
6
1.7739
5
  1.7574
3
1.7581
3
1.7000
1
CCSD         1.8248
14
    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
1.7826
7
1.7614
7
1.6900
2
1.7863
6
1.7584
5
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
1.8507
14
1.8625
13
1.8550
14
1.8402
13
1.8451
14
density functional B1B95 1.9153
7
1.8988
7
1.9157
2
1.8938
2
1.8941
2
1.8973
2
B3LYP 1.8615
14
1.8362
14
1.8620
14
1.8352
14
1.8504
14
1.8459
14
Moller Plesset perturbation MP2 1.8781
14
1.8427
14
1.8736
14
1.8354
14
1.8592
14
1.8617
14
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.