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Computational Chemistry Comparison and Benchmark DataBase
Release 18October 2016
NIST Standard Reference Database 101
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III.G.1.a.

Comparison of levels of theory for P-P


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 1.6572
3
PM3 1.7338
3
PM6 2.0971
11
composite G2 2.0924
10
G3 2.0924
10
G3B3 2.1349
10
G4 2.1141
10
CBS-Q 2.0924
10

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(D+d)Z cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ
hartree fock HF 2.0613
10
2.2762
10
2.0819
10
2.2408
10
2.0780
11
2.0925
10
2.0797
9
2.0933
10
2.0934
10
2.0942
10
2.1382
8
2.0892
11
2.1138
10
2.0972
10
2.1192
9
2.1166
10
2.0973
10
2.0052
3
1.8571
1
2.1384
8
1.8517
1
1.8654
1
1.8519
1
ROHF         1.9562
1
                                   
density functional LSDA 2.1147
10
2.2625
10
2.1043
10
2.2619
10
2.1225
10
2.1225
10
2.1223
10
2.1189
10
2.1189
10
2.1127
10
  1.9020
2
2.1384
10
2.1152
10
1.9765
1
2.1393
10
1.9219
3
1.9714
1
1.8980
1
1.8878
1
1.8873
1
   
SVWN   2.2725
11
    2.1364
9
1.9042
2
2.1110
11
1.8940
2
1.8940
2
1.8928
2
  2.1256
10
1.9109
2
1.8944
2
  1.9125
2
1.8943
2
      1.8873
1
   
BLYP 2.1460
10
2.3356
10
2.1481
10
2.3110
10
2.1337
11
2.1667
10
2.1667
10
2.1661
10
2.1662
10
2.1560
10
  1.9279
2
2.1806
10
2.1586
10
  2.2309
8
    1.9205
1
1.9113
1
1.9109
1
   
B1B95 2.1017
10
2.2635
10
2.0948
10
2.2515
10
2.1069
10
2.1095
10
2.1095
10
2.1095
10
2.1096
10
2.1058
10
  1.8873
2
2.1272
10
2.1060
10
1.9664
1
2.1265
10
1.9105
3
1.9622
1
1.8842
1
1.8766
1
1.8763
1
   
B3LYP 2.1197
10
2.3073
10
2.1192
10
2.2801
10
2.1368
10
2.1365
10
2.1366
10
2.1353
10
1.9302
3
2.1285
10
2.1686
8
2.1282
11
2.1520
10
2.1311
10
2.0373
3
2.1532
10
2.1310
10
2.0359
3
1.8971
1
2.1685
8
1.8884
1
   
B3LYPultrafine         2.1369
10
            1.9036
1
1.9101
2
2.0121
3
  1.9122
2
2.0951
11
      1.8884
1
   
B3PW91 1.8947
3
2.2952
10
2.1073
10
2.2641
10
2.1220
10
2.1220
10
2.1222
10
2.1209
10
1.9218
3
2.1164
10
  1.8965
2
2.1390
10
2.1190
10
  2.1879
8
    1.8924
1
1.8842
1
1.8840
1
   
mPW1PW91 1.8886
3
2.2890
10
1.9122
3
2.2573
10
2.1158
10
2.1158
10
2.1160
10
2.1150
10
2.1150
10
2.1109
10
  1.8914
2
2.1331
10
2.1136
10
  2.1510
9
1.8856
2
  1.8877
1
1.8799
1
1.8797
1
   
M06-2X 1.8525
2
1.9566
2
2.0978
11
1.9669
2
2.0944
11
1.8820
2
1.8823
2
1.8746
2
1.8746
2
1.8766
2
  1.8827
2
1.8902
2
1.8782
2
  1.8929
2
1.8781
2
  1.8793
1
1.8724
1
1.8721
1
   
PBEPBE 1.9150
3
2.3150
10
1.9377
3
2.0362
3
2.1427
10
2.1427
10
2.1427
10
2.1426
10
2.1426
10
2.1352
10
2.1738
8
1.9181
2
2.0338
4
2.1381
10
1.9961
1
1.9270
2
2.1536
9
1.9906
1
1.9129
1
1.9044
1
1.9044
1
   
PBEPBEultrafine         2.1569
9
            1.9189
1
1.9251
2
1.9112
2
  1.9269
2
1.9114
2
      1.9044
1
   
PBE1PBE 1.8671
2
1.8813
2
1.8813
2
1.9773
2
2.0937
11
1.8914
2
1.8916
2
1.8837
2
1.8837
2
1.8839
2
  1.8921
2
1.8992
2
1.8863
2
  1.9016
2
1.8865
2
      1.8807
1
   
HSEh1PBE 1.8683
2
2.2608
11
1.8822
2
1.9792
2
2.1158
10
1.8927
2
2.0952
11
1.8848
2
1.8848
2
1.8849
2
  1.8931
2
1.9003
2
2.0930
11
  1.9029
2
1.8873
2
  1.8894
1
1.8818
1
1.8816
1
   
TPSSh   1.9750
1
1.8952
1
1.9793
1
2.1092
11
1.9020
1
2.1094
11
1.8957
1
  2.1056
11
  1.9030
1
1.9091
1
2.1071
11
  1.9103
1
1.8946
1
      1.8885
1
   
wB97X-D     2.0961
11
  2.1040
11
  2.1040
11
  2.1025
11
    2.1058
11
2.1040
11
2.0981
11
    2.0977
11
           
B97D3   2.1816
11
    2.1171
11
      2.1166
11
              2.1121
11
           
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(D+d)Z cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ
Moller Plesset perturbation MP2 1.9720
3
2.3808
10
2.1081
10
2.3498
10
2.1134
11
2.1266
10
2.1273
10
2.1139
11
2.1282
10
2.1296
10
  2.1307
11
2.1583
10
2.1328
10
2.1374
8
2.1678
10
2.0173
4
1.9532
2
1.9342
1
2.1666
8
1.9203
1
2.1922
7
1.9194
1
MP2=FULL 1.9716
3
2.3820
10
1.9379
3
2.1051
3
2.1239
10
2.1239
10
2.1248
10
2.1273
10
1.9480
3
1.9392
3
  1.9337
2
2.1561
10
2.1135
9
2.1318
8
2.1729
8
1.9122
2
1.9488
2
1.9310
1
2.1527
8
1.9097
1
2.1894
7
1.9136
1
MP3         2.1199
10
  2.1072
11
        1.9018
1
1.9130
1
1.8943
1
        1.9017
1
1.8887
1
1.8896
1
   
MP3=FULL         2.1059
11
  2.1291
10
        1.9031
1
1.9115
1
1.8912
1
            1.8821
1
   
MP4   2.1654
3
    2.1376
10
    2.0801
2
1.9582
3
    1.9428
2
1.9536
2
2.0267
4
  1.9588
2
1.9314
2
  1.9354
1
1.9222
1
1.9226
1
   
MP4=FULL   2.1768
2
    1.9350
2
      1.9297
2
      1.9514
2
1.9249
2
  1.9563
2
1.9214
2
      1.9135
1
   
B2PLYP 1.8895
1
2.0094
1
1.9048
1
2.0161
1
2.1409
10
1.9172
1
1.9171
1
1.9099
1
1.9099
1
1.9090
1
  1.9176
1
1.9247
1
2.1370
10
  1.9270
1
1.9088
1
  1.9118
1
1.9020
1
1.9021
1
   
B2PLYP=FULL 1.8894
1
2.0097
1
1.9044
1
2.0162
1
1.9165
1
1.9165
1
1.9164
1
1.9098
1
1.9098
1
1.9065
1
  1.9179
1
1.9241
1
1.9075
1
  1.9264
1
1.9066
1
      1.8993
1
   
B2PLYP=FULLultrafine         2.2301
1
                                   
Configuration interaction CID   2.0239
3
1.9038
3
2.0281
3
2.1066
10
    1.9875
4
                        1.8766
1
   
CISD   2.0279
3
1.9065
3
2.0314
3
2.1081
10
    1.9113
3
                        1.8788
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(D+d)Z cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ
Quadratic configuration interaction QCISD   2.3566
10
1.9223
3
2.0558
3
2.1246
10
1.9371
3
2.0091
4
2.1255
10
2.1132
9
1.9287
3
  1.9100
2
2.0247
4
1.9288
3
  1.9254
2
1.8992
2
  1.9114
1
1.8955
1
1.8956
1
   
QCISD(T)         2.0195
4
    2.0772
2
      1.9247
2
1.9665
3
1.9447
3
  1.9711
3
1.9446
3
  1.9261
1
1.9110
1
1.9112
1
   
Coupled Cluster CCD   2.0433
3
1.9160
3
2.0477
3
2.1202
10
1.9301
3
1.9295
3
2.0000
4
1.9224
3
1.9231
3
  1.9035
2
2.0233
4
1.9230
3
  1.9494
3
1.9228
3
  1.9061
1
1.8897
1
1.8902
1
   
CCSD         2.1232
10
    2.0676
2
      1.9071
2
1.9179
2
1.8965
2
1.8894
1
1.9233
2
1.8972
2
1.8895
1
1.9095
1
1.8936
1
1.8938
1
   
CCSD=FULL         1.9009
2
            1.9073
2
1.9159
2
1.8915
2
1.8866
1
1.9211
2
1.8885
2
1.8859
1
    1.8848
1
   
CCSD(T)   2.0210
1
    2.1467
9
2.0753
2
1.9210
1
2.0765
2
1.9126
1
  1.9071
1
1.9230
2
2.1553
9
2.1262
9
1.9054
1
2.1628
9
2.1266
9
1.9053
1
1.9249
1
1.9095
1
1.9101
1
2.2018
7
2.1663
7
CCSD(T)=FULL         2.1189
9
            1.9235
2
2.1693
8
2.1316
8
1.9023
1
2.1775
8
1.9052
2
1.9020
1
1.9231
1
1.9058
1
1.9011
1
2.1990
7
1.9052
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(D+d)Z cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVDZ 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 2.2403
10
2.1252
10
2.2426
10
2.1210
10
2.2656
10
2.2657
10
density functional B1B95 2.3343
8
2.2033
8
       
B3LYP 2.2966
10
2.1682
10
2.2943
10
2.1655
10
2.3215
10
2.3056
10
Moller Plesset perturbation MP2 2.3557
10
2.1730
10
2.3506
10
2.1695
10
2.3798
10
2.3725
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.