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III.G.1.a.

Comparison of levels of theory for P-S


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 1.7674
3
PM3 1.8313
4
PM6 1.7899
4
composite G2 1.9398
4
G3 1.9398
4
G3B3 1.9587
4
G4 1.9432
4
CBS-Q 1.9398
4

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
hartree fock HF 1.9082
4
2.1214
4
1.9272
4
2.0872
4
1.9553
6
1.9398
4
1.9390
4
1.9894
3
1.9384
4
1.9271
4
1.9135
1
1.9461
4
1.9499
4
1.9303
4
1.9224
4
1.9492
4
1.9282
4
1.9210
4
ROHF   1.9958
1
1.8738
1
  1.9475
2
1.8828
1
1.8828
1
1.8779
1
        1.8925
1
1.8789
1
       
density functional LSDA 1.9504
4
1.9682
4
1.9377
4
2.0616
4
1.9516
4
1.9516
4
1.9479
4
1.9457
4
1.9457
4
1.9377
4
    1.9599
4
1.9385
4
1.9145
2
1.9554
4
1.9437
3
1.9123
2
SVWN   2.0673
4
    1.9283
3
  1.9478
4
                     
BLYP 1.9767
4
2.1082
4
1.9700
4
2.1000
4
1.9860
4
1.9860
4
1.9823
4
1.9835
4
1.9836
4
1.9720
4
    1.9936
4
1.9729
4
  1.9548
1
   
B1B95 1.9382
4
1.9589
4
1.9286
4
2.0502
4
1.9388
4
1.9395
4
1.9360
4
1.9362
4
1.9362
4
1.9301
4
    1.9490
4
1.9308
4
1.9354
3
1.9812
3
1.9958
2
1.9315
3
B3LYP 1.9525
4
2.0778
4
1.9448
4
2.0710
4
1.9587
4
1.9587
4
1.9557
4
1.9554
4
1.9682
3
1.9466
4
1.9018
1
1.9606
4
1.9671
4
1.9477
4
1.9404
4
1.9635
4
1.9435
4
1.9372
4
B3LYPultrafine         1.9589
4
                      1.9820
3
 
B3PW91 1.9561
3
2.0677
4
1.9368
4
2.0592
4
1.9479
4
1.9479
4
1.9449
4
1.9439
4
1.9561
3
1.9372
4
    1.9571
4
1.9383
4
  1.9222
1
   
mPW1PW91 1.9503
3
2.0614
4
1.9428
3
2.0532
4
1.9422
4
1.9422
4
1.9394
4
1.9384
4
1.9385
4
1.9319
4
    1.9515
4
1.9334
4
  1.9172
1
   
M06-2X         1.9357
4
                         
PBEPBE 1.9743
3
2.0907
4
1.9677
3
2.0944
3
1.9688
4
1.9688
4
1.9651
4
1.9658
4
1.9658
4
1.9565
4
1.9135
1
  1.9769
4
1.9578
4
1.9621
3
2.0374
1
1.9694
2
1.9573
3
PBEPBEultrafine         1.9339
1
                         
PBE1PBE         1.9419
4
                         
HSEh1PBE         1.9194
3
                         
TPSSh         1.9442
4
  1.9421
4
            1.9379
4
       
Moller Plesset perturbation MP2 1.9736
3
2.1208
4
1.9167
4
2.1071
4
1.9276
4
1.9276
4
1.9248
4
1.9240
4
1.9240
4
1.9520
4
  1.9343
4
1.9444
4
1.9259
4
1.8896
3
1.9477
4
1.9236
4
1.8891
3
MP2=FULL 1.9733
3
2.1217
4
1.9472
3
2.1180
3
1.9257
4
1.9257
4
1.9231
4
1.9239
4
1.9594
3
1.9494
3
    1.9430
4
1.9537
3
1.8872
3
1.9344
2
1.9942
1
1.9170
2
MP3         1.9206
4
  1.9381
4
                     
MP3=FULL         1.9371
4
                         
MP4   2.2817
3
    1.9439
4
    1.8308
1
1.9786
3
        1.9098
3
       
B2PLYP         1.9581
4
                1.9408
4
       
Configuration interaction CID   2.0930
3
1.9335
3
2.0834
3
1.9212
4
    1.9163
4
                   
CISD   2.1112
3
1.9379
3
2.0989
3
1.9314
4
    1.9473
3
                   
Quadratic configuration interaction QCISD   2.1412
4
1.9524
3
2.1392
3
1.9540
4
1.9670
3
1.9519
4
1.9505
4
1.9648
3
1.9589
3
    1.9710
4
1.9593
3
       
QCISD(T)         1.9624
4
    1.9186
1
        1.9949
3
1.9703
3
  1.9976
3
1.9676
3
 
Coupled Cluster CCD   2.1022
3
1.9391
3
2.0924
3
1.9241
4
1.9524
3
1.9496
3
1.9201
4
1.9494
3
1.9476
3
    1.9410
4
1.9482
3
  1.9732
3
1.9452
3
 
CCSD         1.9496
4
                         
CCSD(T)         1.9230
1
1.9230
1
  1.9156
1
    1.9016
1
  1.9923
3
1.9538
4
2.0116
1
1.9949
3
1.9651
3
 
CCSD(T)=FULL         1.9403
2
                  2.0082
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 2.0999
4
1.9629
4
2.0974
4
1.9579
4
2.1200
4
2.1057
4
density functional B1B95   1.9388
1
       
B3LYP 2.0939
4
1.9803
4
2.0908
4
1.9777
4
2.0978
4
2.0762
4
Moller Plesset perturbation MP2 2.1305
4
1.9545
4
2.1242
4
1.9484
4
2.1288
4
2.1111
4
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.