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III.G.1.a.

Comparison of levels of theory for Na-Br


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 2.4203
1
PM3 2.6523
1
PM6 2.5829
3
composite G2 2.6984
3
G3B3 2.7100
3
G4 2.6985
3
CBS-Q 2.7044
3

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 2.5485
3
2.7899
3
2.6375
3
2.7341
3
2.6984
6
2.6984
3
2.7193
3
2.7560
3
2.7560
3
2.6952
3
2.5427
1
2.7846
3
2.8823
2
2.7551
3
2.5485
1
2.7664
3
2.7505
3
2.5481
1
density functional LSDA 2.4720
3
2.5820
3
2.5376
3
2.6361
3
2.6071
3
2.6071
3
2.5423
2
2.6507
3
2.6507
3
2.5989
3
    2.5510
2
2.6541
3
  2.6637
3
2.7273
2
 
SVWN   2.7071
3
    2.5125
2
  2.6323
3
                     
BLYP 2.5267
3
2.7511
3
2.5924
3
2.7001
3
2.6745
3
2.6745
3
2.7056
3
2.7382
3
2.7382
3
2.6674
3
    2.8401
2
2.7408
3
       
B1B95 2.5280
3
2.5552
2
2.4971
2
2.5780
2
2.6659
3
2.6663
3
2.5138
1
2.5232
1
2.5232
1
2.5631
2
    2.5983
2
2.7207
3
  2.6150
2
2.8054
2
 
B3LYP 2.5210
3
2.8413
2
2.5857
3
2.6895
3
2.6617
3
2.6617
3
2.6893
3
2.7204
3
2.7204
3
2.6559
3
  2.7449
3
2.7251
3
2.7223
3
2.5221
1
2.7298
3
2.7151
3
2.5224
1
B3LYPultrafine         2.7492
2
                      2.7091
3
 
B3PW91 2.5265
3
2.7783
3
2.6137
3
2.7061
3
2.6740
3
2.6740
3
2.6979
3
2.7290
3
2.7290
3
2.6669
3
    2.8551
2
2.7312
3
       
mPW1PW91 2.5223
3
2.7618
3
2.6023
3
2.6972
3
2.6652
3
2.6652
3
2.6891
3
2.7178
3
2.7178
3
2.6591
3
    2.8409
2
2.7202
3
       
M06-2X         2.6477
3
                         
PBEPBE 2.5181
3
2.7534
3
2.5948
3
2.6927
3
2.6646
3
2.6646
3
2.6917
3
2.7186
3
2.7186
3
2.6578
3
2.5216
1
  2.8309
2
2.7224
3
       
PBEPBEultrafine         2.4918
1
                         
PBE1PBE         2.6574
3
                         
HSEh1PBE         2.6590
3
                         
TPSSh         2.6169
3
  2.6313
3
            2.6434
3
       
Moller Plesset perturbation MP2 2.5386
3
2.7924
3
2.6330
3
2.7381
3
2.6551
4
2.7005
3
2.7235
3
2.7265
3
2.7265
3
2.6965
3
  2.7828
3
2.7636
3
2.5443
2
2.5457
1
2.7761
3
2.5530
1
2.5480
1
MP2=FULL 2.5352
3
2.7932
3
2.6271
3
2.7379
3
2.6447
4
2.6887
3
2.7109
3
2.7119
3
2.7119
3
2.6661
3
    2.8655
2
2.5308
2
2.5068
1
2.5625
1
   
MP3         2.6986
3
  2.6264
3
                     
MP3=FULL         2.6224
3
  2.6373
3
                     
MP4 2.3185
1
2.7935
3
    2.6979
3
      2.7220
3
2.5266
1
      2.5482
1
       
B2PLYP         2.6680
3
                2.6425
3
       
Configuration interaction CID   2.7926
3
2.7159
2
2.8337
2
2.6981
3
    2.8206
2
2.5352
1
2.5227
1
               
CISD   2.7932
3
2.7158
2
2.8339
2
2.6982
3
    2.8207
2
2.5357
1
2.5231
1
               
Quadratic configuration interaction QCISD 2.3183
1
2.7939
3
2.7153
2
2.7400
3
2.6989
3
2.6989
3
2.7218
3
2.7241
3
2.7241
3
2.6958
3
    2.7632
3
2.7356
3
       
QCISD(T)   2.5853
1
2.4672
1
2.5515
1
2.6980
3
  2.5466
1
2.5356
1
2.5356
1
2.5268
1
    2.8681
2
2.8295
2
  2.8783
2
2.8350
2
 
Coupled Cluster CCD 2.3184
1
2.7928
3
2.7153
2
2.7393
3
2.6985
3
2.6985
3
2.7216
3
2.7237
3
2.7237
3
2.6955
3
    2.7628
3
2.7356
3
  2.8762
2
2.8330
2
 
CCSD         2.6986
3
                         
CCSD(T)     2.4671
1
2.5513
1
2.5207
1
  2.5207
1
2.5355
1
2.5355
1
2.5266
1
2.5495
1
  2.7628
3
2.7358
3
  2.7782
3
2.7415
3
 
CCSD(T)=FULL         2.7730
2
                         

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 2.9369
3
  2.8674
3
  2.8725
3
2.8740
3
density functional B1B95 2.6380
1
         
B3LYP 2.9165
3
  2.8656
3
  2.8664
3
2.8348
3
Moller Plesset perturbation MP2 2.9462
3
  2.8774
3
  2.8524
3
2.8698
3
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.