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Comparison of levels of theory for Na-K


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 PM3 3.4133
1
PM6 4.3216
2
composite G2 3.9599
2
G3 3.9675
2
G3B3 3.8761
2
G4 3.8951
2
CBS-Q 3.9599
2

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
hartree fock HF 2.9844
2
3.9988
2
3.9845
2
3.9884
2
3.9654
2
3.9657
2
3.9671
2
3.9784
2
3.9784
2
3.9772
2
  4.0270
2
 
ROHF   4.2915
1
4.2543
1
4.2921
1
4.2447
1
4.2447
1
4.2432
1
4.2684
1
4.2684
1
    4.3524
1
 
density functional LSDA 2.9327
2
3.4527
2
3.4527
2
3.7213
2
3.6897
2
3.9748
1
3.6891
2
3.6898
2
3.6898
2
3.6812
2
  3.7666
2
 
BLYP 2.9843
2
3.8317
2
3.7919
2
3.8566
2
3.8439
2
3.8265
2
3.8252
2
3.8302
2
3.8302
2
3.8209
2
  3.9031
2
 
B1B95 2.9649
2
  3.8363
2
3.5097
1
3.5128
1
3.5128
1
3.5131
1
3.8329
2
3.8329
2
3.8162
2
  3.8949
2
 
B3LYP 2.9686
2
3.8159
2
3.7826
2
3.8261
2
3.7957
2
3.7957
2
3.7950
2
3.8027
2
3.8027
2
3.7940
2
  3.8699
2
 
B3LYPultrafine   4.1341
1
    3.7961
2
4.0826
1
4.0811
1
4.1061
1
      4.2144
1
 
B3PW91 2.9764
2
3.8942
2
3.8732
2
3.8664
2
3.8321
2
3.8321
2
3.8316
2
3.8460
2
3.8460
2
3.8342
2
  3.9133
2
 
mPW1PW91 2.9705
2
3.8891
2
3.8684
2
3.8636
2
3.8288
2
3.8288
2
3.8286
2
3.8457
2
3.8457
2
3.8321
2
  3.9121
2
 
M06-2X 2.9205
2
3.7818
2
3.7480
2
3.7287
2
3.7054
2
3.7054
2
3.7049
2
3.7018
2
4.0144
1
3.7039
2
3.6907
2
3.7981
2
 
PBEPBE 2.9751
2
3.8584
2
3.8310
2
3.8572
2
3.8241
2
3.8241
2
3.8231
2
3.8373
2
3.8373
2
3.8237
2
  3.9064
2
 
PBEPBEultrafine   4.1770
1
    4.1095
1
4.1095
1
4.1077
1
4.1443
1
      4.2499
1
 
PBE1PBE 3.0957
1
  4.1321
1
4.1635
1
4.0954
1
4.0954
1
4.0942
1
4.1314
1
4.1314
1
4.1070
1
  4.2350
1
 
HSEh1PBE 2.9651
2
3.8701
2
3.8466
2
3.8604
2
3.8249
2
3.8249
2
3.8244
2
3.8390
2
3.8390
2
3.8268
2
  3.9066
2
 
TPSSh 3.1084
1
4.2082
1
4.1587
1
4.1920
1
3.8651
2
4.1216
1
3.8646
2
4.1677
1
4.1677
1
3.8698
2
  4.2737
1
 
wB97X-D 3.1027
1
4.2855
1
3.9222
2
4.2269
1
3.8473
2
4.1585
1
3.8477
2
4.1897
1
3.8630
2
4.1856
1
  3.9279
2
3.5364
1
B97D3   3.6187
1
    3.6099
1
  3.6100
1
  3.6060
1
  3.6051
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
Moller Plesset perturbation MP2 2.9831
2
3.9985
2
3.9751
2
3.9843
2
3.8891
2
3.8821
2
3.8828
2
3.8657
2
3.8508
2
3.8077
2
  4.0278
2
 
MP2=FULL 2.9651
2
3.9934
2
3.9466
2
3.9821
2
3.8705
2
3.8705
2
3.8706
2
3.8261
2
3.8261
2
3.7681
2
  4.0018
2
 
ROMP2 3.1198
1
  4.2544
1
4.2888
1
4.1951
1
4.1952
1
4.1920
1
4.1708
1
4.1708
1
4.1721
1
  4.3523
1
 
MP3         3.8702
2
  3.8797
2
        4.3516
1
 
MP3=FULL   4.2858
1
4.2222
1
4.2857
1
3.8724
2
4.1758
1
3.8718
2
4.1511
1
4.1511
1
4.1137
1
  4.3322
1
 
MP4   3.9927
2
    3.8694
2
      3.8489
2
    4.3515
1
 
MP4=FULL   4.2854
1
    4.1728
1
      4.1430
1
       
B2PLYP 3.0989
1
4.1697
1
4.1325
1
4.1803
1
4.1020
1
4.1020
1
4.1007
1
4.1101
1
4.1101
1
4.0944
1
  4.2440
1
 
B2PLYP=FULL 3.0927
1
4.1683
1
4.1233
1
4.1795
1
4.0984
1
4.0984
1
4.0969
1
4.1032
1
4.1032
1
4.0782
1
  4.2368
1
 
B2PLYP=FULLultrafine 3.0931
1
4.1707
1
4.1257
1
4.1813
1
4.0995
1
4.0995
1
4.0980
1
4.1044
1
4.1044
1
4.0791
1
  4.2367
1
 
Configuration interaction CID   3.9926
2
3.9671
2
3.9800
2
3.8727
2
    3.8650
2
         
CISD   3.9997
2
3.9697
2
3.9874
2
3.8759
2
    3.8641
2
         
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
Quadratic configuration interaction QCISD   3.9997
2
3.9697
2
3.9877
2
3.8776
2
3.8776
2
3.8787
2
3.8630
2
3.8630
2
3.8076
2
  4.0298
2
 
QCISD(T)         3.8774
2
    4.1624
1
      4.0297
2
 
QCISD(T)=FULL         4.1719
1
  4.1686
1
           
QCISD(TQ)         4.1831
1
  4.1802
1
           
QCISD(TQ)=FULL         4.1720
1
  4.1688
1
           
Coupled Cluster CCD   3.9926
2
3.9670
2
3.9802
2
3.8819
2
3.8723
2
3.8730
2
3.8574
2
3.8574
2
3.8121
2
  4.0203
2
 
CCSD         3.8775
2
        4.1647
1
  4.3516
1
 
CCSD=FULL         4.1728
1
        4.1111
1
  4.3315
1
 
CCSD(T)         3.8776
2
4.1830
1
  4.1624
1
      4.0297
2
 
CCSD(T)=FULL         3.8657
2
            4.0102
2
 
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

average calculated bond lengths (Å)
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD cc-pVTZ-PP aug-cc-pVTZ-PP Def2TZVPP
hartree fock HF 4.0582
2
  4.0333
2
  4.0188
2
3.9544
2
    3.6558
1
density functional B3LYP 4.0393
2
  4.0155
2
  3.8866
2
3.8032
2
    3.5518
1
PBEPBE                 3.5689
1
wB97X-D 4.3037
1
  4.2944
1
  4.2469
1
4.1389
1
     
Moller Plesset perturbation MP2 4.0767
2
  4.0435
2
  4.0254
2
3.9484
2
    3.6429
1
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.