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
VIInput and output files
VIITutorials and Units
VIIILinks to other sites
IXFeedback
XOlder CCCBDB versions
XIIGeometries
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers
XXIOddities

NIST policy on privacy, security, and accessibility.

Please rate our products
© 2013 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

The National Institute of Standards and Technology (NIST) is an agency of the U.S. Department of Commerce.

Please send questions, comments, corrections, additions and suggestions to cccbdb@nist.gov.

return to home page

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 1.6730
4
PM3 1.7748
4
PM6 2.0971
11
composite G2 2.0780
11
G3 2.0779
11
G3B3 2.1221
11
G4 2.1141
10
CBS-Q 2.0779
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(D+d)Z cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ
hartree fock HF 2.0490
11
2.2545
11
2.0678
11
2.2222
11
2.0780
11
2.0780
11
2.0651
10
2.0779
11
2.0780
11
2.0792
11
2.1382
8
2.0892
11
2.0983
11
2.0822
11
2.1000
10
2.1013
11
2.0823
11
1.9858
4
1.8571
1
2.1384
8
1.8517
1
1.8654
1
1.8519
1
ROHF         1.9562
1
                                   
density functional LSDA 2.1045
11
2.2372
11
2.0933
11
2.2473
11
2.1111
11
2.1111
11
2.1110
11
2.1067
11
2.1067
11
2.1013
11
  1.9020
2
2.1261
11
2.1035
11
1.9786
2
2.1270
11
1.9378
4
1.9761
2
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 2.1350
11
2.3181
11
2.1354
11
2.2949
11
2.1337
11
2.1539
11
2.1539
11
2.1524
11
2.1524
11
2.1430
11
  1.9279
2
2.1669
11
2.1453
11
  2.2309
8
    1.9205
1
1.9113
1
1.9109
1
   
B1B95 2.0910
11
2.2364
11
2.0831
11
2.2360
11
2.0951
11
2.0974
11
2.0975
11
2.0966
11
2.0967
11
2.0935
11
  1.8873
2
2.1142
11
2.0938
11
1.9666
2
2.1138
11
1.9257
4
1.9645
2
1.8842
1
1.8766
1
1.8763
1
   
B3LYP 2.1086
11
2.2889
11
2.1066
11
2.2637
11
2.1238
11
2.1235
11
2.1235
11
2.1215
11
1.9435
4
2.1153
11
2.1686
8
2.1282
11
2.1381
11
2.1177
11
2.0226
4
2.1393
11
2.1176
11
2.0215
4
1.8971
1
2.1685
8
1.8884
1
   
B3LYPultrafine         2.1238
11
            1.9036
1
1.9101
2
2.0121
3
  1.9122
2
2.0951
11
      1.8884
1
   
B3PW91 1.9188
4
2.2770
11
2.0952
11
2.2482
11
2.1095
11
2.1095
11
2.1097
11
2.1076
11
1.9349
4
2.1036
11
  1.8965
2
2.1256
11
2.1061
11
  2.1879
8
    1.8924
1
1.8842
1
1.8840
1
   
mPW1PW91 1.9125
4
2.2707
11
1.9262
4
2.2414
11
2.1032
11
2.1032
11
2.1034
11
2.1017
11
2.1017
11
2.0981
11
  1.8914
2
2.1196
11
2.1007
11
  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 1.9399
4
2.2980
11
1.9530
4
2.0567
4
2.1308
11
2.1309
11
2.1309
11
2.1299
11
2.1299
11
2.1231
11
2.1738
8
1.9181
2
2.0305
5
2.1258
11
1.9970
2
1.9270
2
2.1536
9
1.9943
2
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
      2.1025
11
        2.0981
11
    2.0977
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 1.9989
4
2.3712
11
2.0979
11
2.3377
11
2.1134
11
2.1162
11
2.1168
11
2.1139
11
2.1165
11
2.1180
11
  2.1307
11
2.1464
11
2.1208
11
2.1211
9
2.1553
11
2.0141
5
1.9657
3
1.9342
1
2.1666
8
1.9203
1
2.1922
7
1.9194
1
MP2=FULL 1.9984
4
2.3726
11
1.9521
4
2.1334
4
2.1135
11
2.1135
11
2.1143
11
2.1156
11
1.9608
4
1.9526
4
  1.9337
2
2.1442
11
2.1017
10
2.1158
9
2.1729
8
1.9122
2
1.9614
3
1.9310
1
2.1527
8
1.9097
1
2.1894
7
1.9136
1
MP3         2.1081
11
  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   2.1728
4
    2.1259
11
    2.0801
2
1.9686
4
    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   2.0482
4
1.9183
4
2.0485
4
2.0944
11
    1.9822
5
                        1.8766
1
   
CISD   2.0524
4
1.9210
4
2.0519
4
2.0960
11
    1.9245
4
                        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   2.3388
11
1.9364
4
2.0770
4
2.1125
11
1.9507
4
2.0055
5
2.1122
11
2.0999
10
1.9424
4
  1.9100
2
2.0214
5
1.9421
4
  1.9254
2
1.8992
2
  1.9114
1
1.8955
1
1.8956
1
   
QCISD(T)         2.0166
5
    2.0772
2
      1.9247
2
1.9811
4
1.9585
4
  1.9855
4
1.9585
4
  1.9261
1
1.9110
1
1.9112
1
   
Coupled Cluster CCD   2.0699
4
1.9303
4
2.0690
4
2.1080
11
1.9441
4
1.9435
4
1.9947
5
1.9353
4
1.9369
4
  1.9035
2
2.0192
5
1.9363
4
  1.9635
4
1.9363
4
  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
    2.1324
10
2.0753
2
1.9210
1
2.0765
2
1.9126
1
  1.9071
1
1.9230
2
2.1422
10
2.1133
10
1.9054
1
2.1492
10
2.1138
10
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 2.2234
11
2.1101
11
2.2256
11
2.1057
11
2.2458
11
2.2447
11
density functional B1B95 2.3343
8
2.2033
8
       
B3LYP 2.2811
11
2.1545
11
2.2791
11
2.1519
11
2.3032
11
2.2872
11
Moller Plesset perturbation MP2 2.3447
11
2.1613
11
2.3400
11
2.1577
11
2.3675
11
2.3612
11
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.