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III.G.1.a.

Comparison of levels of theory for Br-Li


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 2.3317
2
PM3 2.0865
3
PM6 2.6820
3
composite G2 2.3515
3
G3B3 2.3656
3
G4 2.3516
3
CBS-Q 2.3636
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 2.1898
3
2.4157
3
2.3299
3
2.3933
3
2.3512
6
2.3512
3
2.3771
3
2.3640
3
2.3640
3
2.3441
3
2.1962
1
2.4009
3
2.5031
2
2.4519
2
2.1968
1
2.3999
3
2.3601
3
2.1967
1
ROHF         2.4323
2
                         
density functional LSDA 2.1642
3
2.2946
3
2.2730
3
2.3293
3
2.2936
3
2.2936
3
2.3228
3
2.3034
3
2.3034
3
2.2811
3
    2.3531
3
2.3031
3
  2.3346
3
2.3662
2
 
SVWN   2.3559
3
    2.2017
2
  2.3228
3
                     
BLYP 2.1876
3
2.3824
3
2.3040
3
2.3612
3
2.3300
3
2.3300
3
2.3635
3
2.2573
2
2.2573
2
2.3241
3
    2.4750
2
2.4400
2
       
B1B95 2.1892
3
2.3298
3
2.3086
3
2.3679
3
2.3305
3
2.3308
3
2.5675
1
2.4300
2
2.4300
2
2.4035
2
    2.3903
3
2.3469
3
  2.2720
2
   
B3LYP 2.1808
3
2.3779
3
2.2980
3
2.3564
3
2.3221
3
2.3221
3
2.3527
3
2.3397
3
2.3397
3
2.3146
3
  2.3763
3
2.3794
3
2.4247
2
2.1769
1
2.3728
3
2.3342
3
2.1771
1
B3LYPultrafine         2.3222
3
                      2.3410
3
 
B3PW91 2.1887
3
2.3980
3
2.3131
3
2.3714
3
2.3337
3
2.3337
3
2.3624
3
2.3458
3
2.3458
3
2.3256
3
    2.4853
2
2.4318
2
       
mPW1PW91 2.1849
3
2.3912
3
2.3073
3
2.3658
3
2.3279
3
2.3279
3
2.3569
3
2.3383
3
2.3383
3
2.3194
3
    2.4768
2
2.4230
2
       
M06-2X         2.3213
3
                         
PBEPBE 2.1866
3
2.3863
3
2.3053
3
2.3611
3
2.3266
3
2.3266
3
2.3584
3
2.3420
3
2.3420
3
2.3195
3
2.1821
1
  2.4732
2
2.4262
2
       
PBEPBEultrafine         2.1744
1
                         
PBE1PBE         2.3223
3
                         
HSEh1PBE         2.3243
3
                         
TPSSh         2.3532
3
  2.3728
3
            2.3645
3
       
Moller Plesset perturbation MP2 2.1843
3
2.4107
3
2.3299
3
2.3963
3
2.3151
4
2.3544
3
2.3824
3
2.3443
3
2.3443
3
2.3414
3
  2.3477
4
2.4037
3
2.3120
4
2.1870
1
2.4088
3
2.3118
4
2.1904
1
MP2=FULL 2.1845
3
2.4103
3
2.3270
3
2.3944
3
2.3054
4
2.3436
3
2.3702
3
2.3327
3
2.3327
3
2.3057
3
  2.2131
1
2.4847
2
2.3253
3
2.1683
1
2.2083
1
2.1675
1
 
MP3         2.3531
3
  2.3672
3
                     
MP3=FULL         2.3603
3
  2.3792
3
                     
MP4 2.0532
1
2.4109
3
    2.3522
3
      2.3407
3
2.1838
1
      2.1937
1
       
B2PLYP         2.3285
3
                2.4528
2
       
Configuration interaction CID   2.4109
3
2.4043
2
2.4802
2
2.3525
3
    2.4212
2
2.1857
1
2.1802
1
               
CISD   2.4115
3
2.4043
2
2.4805
2
2.3526
3
    2.4213
2
2.1861
1
2.1807
1
               
Quadratic configuration interaction QCISD 2.0506
1
2.4119
3
2.4044
2
2.3985
3
2.3532
3
2.3532
3
2.3808
3
2.3421
3
2.3421
3
2.3402
3
    2.4028
3
2.3514
3
       
QCISD(T)   2.2460
1
2.1826
1
2.2339
1
2.3524
3
  2.2227
1
2.1869
1
2.1869
1
2.1840
1
    2.4877
2
2.4307
2
  2.4941
2
2.4268
2
 
Coupled Cluster CCD 2.0454
1
2.4110
3
2.4043
2
2.3977
3
2.3529
3
2.3529
3
2.3805
3
2.3418
3
2.3418
3
2.3399
3
    2.4024
3
2.4307
2
  2.4923
2
2.4261
2
 
CCSD         2.4314
2
                         
CCSD(T)     2.1825
1
2.2336
1
2.1960
1
  2.1960
1
2.1867
1
2.1867
1
2.1838
1
2.2000
1
  2.4023
3
2.3516
3
  2.4100
3
2.3498
3
 
CCSD(T)=FULL         2.4184
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 2.5035
3
  2.4474
3
  2.4973
3
2.4780
3
density functional B3LYP 2.4943
3
  2.4489
3
  2.4635
3
2.4491
3
Moller Plesset perturbation MP2 2.5130
3
  2.4528
3
  2.4775
3
2.4722
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.