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III.G.1.a.

Comparison of levels of theory for C-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 1.6605
9
PM3 1.7240
14
PM6 1.8406
30
composite G2 1.8524
42
G3 1.8185
27
G3B3 1.8838
43
G4 1.9297
32
CBS-Q 1.8175
30

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
hartree fock HF 1.9047
27
1.8966
42
1.8537
42
1.8865
42
1.9132
64
1.8515
42
1.8474
42
1.8529
42
1.8501
41
1.8275
40
1.9176
13
1.8410
43
1.8554
42
1.8499
42
1.7721
22
1.8422
38
1.8341
35
1.7457
18
1.7145
1
1.7094
1
ROHF   1.9530
15
1.8996
15
1.9409
15
1.8996
15
1.8991
15
1.8949
15
1.9006
15
1.9004
15
    1.8598
2
1.9028
15
1.8968
15
1.8716
10
1.8772
11
1.8728
11
1.8714
10
  1.7094
1
density functional LSDA 1.8613
42
1.8519
42
1.8393
42
1.8771
42
1.8417
42
1.8412
42
1.8360
42
1.8442
42
1.8442
42
1.8055
38
  1.6400
10
1.8462
42
1.8371
42
  1.8329
38
1.7675
22
    1.6685
1
SVWN   1.8357
25
    1.8003
25
1.6418
10
1.7953
25
1.6411
10
1.6412
10
1.6237
10
    1.6448
10
1.6354
10
  1.6440
10
1.6350
10
     
BLYP 1.8827
32
1.9327
43
1.8935
43
1.9372
43
1.9001
43
1.8997
43
1.8935
43
1.9039
43
1.9013
42
1.8682
41
  1.6836
10
1.9042
43
1.8972
43
  1.9688
11
      1.7126
1
B1B95 1.8634
41
1.8587
41
1.8466
41
1.8821
41
1.8459
41
1.8465
41
1.8436
42
1.8494
41
1.8493
41
1.8221
40
  1.6467
10
1.8503
41
1.8433
41
  1.8356
37
1.7821
23
    1.6822
1
B3LYP 1.8815
42
1.9053
40
1.8692
42
1.9087
42
1.8727
42
1.8723
42
1.8670
42
1.8754
42
1.8727
41
1.8434
40
  1.8613
43
1.8762
42
1.8694
42
1.7628
18
1.8621
38
1.8410
33
1.7625
18
1.7055
1
1.6984
1
B3LYPultrafine         1.8403
28
              1.5834
7
1.7612
14
  1.5837
7
1.9004
37
     
B3PW91 1.8530
32
1.8988
43
1.8592
43
1.8958
43
1.8596
42
1.8602
43
1.8545
43
1.8629
43
1.8603
42
1.8325
41
  1.6541
10
1.8640
43
1.8572
43
  1.9275
11
      1.6898
1
mPW1PW91 1.8609
42
1.8918
42
1.8527
42
1.8880
42
1.8518
41
1.8525
42
1.8473
42
1.8552
42
1.8526
41
1.8255
40
  1.6502
10
1.8562
42
1.8498
42
  1.8338
34
1.7794
22
    1.6870
1
M06-2X 1.7849
17
1.8134
17
1.7799
17
1.8055
17
1.8410
32
1.7736
17
1.7690
17
1.7756
17
1.7758
17
1.7524
17
  1.6527
10
1.7763
17
1.7717
17
  1.7180
13
1.6953
12
    1.6920
1
PBEPBE 1.8610
31
1.9099
42
1.8705
42
1.9102
42
1.8716
41
1.8722
42
1.8664
42
1.8761
42
1.8735
41
1.8427
40
1.9498
6
1.6665
10
1.8763
42
1.8696
42
  1.8529
34
1.8358
31
  1.7015
1
1.6959
1
PBEPBEultrafine         1.8486
27
              1.5876
7
1.5816
7
  1.5877
7
1.5821
7
     
PBE1PBE 1.6802
10
1.6562
10
1.6562
10
1.6830
10
1.8267
37
1.6494
10
1.6460
10
1.6493
10
1.6493
10
1.6325
10
  1.6491
10
1.6515
10
1.6445
10
  1.6509
10
1.6444
10
     
HSEh1PBE 1.7908
17
1.8094
17
1.7762
17
1.8097
17
1.8422
32
1.7748
17
1.7699
17
1.7763
17
1.7764
17
1.7522
17
  1.6505
10
1.7776
17
1.7715
17
  1.7185
13
1.6942
12
    1.6864
1
TPSSh         1.9043
37
  1.8985
37
            1.9016
37
           
Moller Plesset perturbation MP2 1.8541
31
1.9180
42
1.8708
42
1.9117
42
1.9032
51
1.8617
42
1.8757
56
1.8560
42
1.8524
41
1.8250
40
  1.8428
43
1.8599
42
1.8708
42
1.4775
7
1.8475
38
1.8253
21
1.4426
6
1.7005
1
1.6884
1
MP2=FULL 1.8539
31
1.9175
42
1.8700
42
1.9101
42
1.8986
51
1.8574
42
1.8523
42
1.8528
42
1.8491
41
1.8083
40
  1.6538
10
1.8579
42
1.8645
43
1.4740
7
1.7995
25
1.7631
22
1.5172
4
1.6981
1
1.6829
1
ROMP2 1.8218
4
1.7923
4
1.7923
4
1.8513
4
1.7739
4
1.7716
4
1.7691
4
1.7682
4
1.7664
4
1.7541
4
  1.8372
2
1.7742
4
1.7564
4
  1.7770
4
       
MP3         1.8672
41
  1.9042
37
                         
MP3=FULL         1.9008
37
  1.8926
36
                         
MP4 1.9234
2
1.9292
41
    1.8732
41
      1.8337
28
    1.5822
7
1.5866
7
1.7821
21
  1.3028
4
1.2926
4
    1.6974
1
MP4=FULL   1.6172
7
    1.5826
7
      1.5801
7
      1.5850
7
1.2866
4
  1.5854
7
1.2879
2
     
B2PLYP         1.9338
15
                1.8848
26
           
B2PLYP=FULLultrafine         1.9421
7
                             
Configuration interaction CID   1.9116
43
1.8605
41
1.9004
41
1.8572
43
    1.8475
40
1.9167
12
                     
CISD   1.9139
43
1.8615
41
1.9029
41
1.8567
42
    1.8486
40
1.9179
12
                     
Quadratic configuration interaction QCISD 1.9262
2
1.9249
42
1.8708
39
1.9153
40
1.8691
42
1.8666
41
1.8618
41
1.8613
41
1.8557
39
1.8286
38
  1.6598
10
1.8482
34
1.8137
28
  1.8020
23
1.7809
21
  1.7085
1
1.6974
1
QCISD(T)         1.8698
40
      1.9008
1
    1.5362
7
1.8222
25
1.7889
22
  1.6690
10
1.5265
7
     
Coupled Cluster CCD 1.9247
2
1.9193
42
1.8676
39
1.9120
41
1.8637
41
1.8610
40
1.8583
41
1.8577
41
1.8520
39
1.8257
38
  1.6562
10
1.8444
34
1.8107
28
  1.7989
23
1.7309
16
  1.7067
1
1.6959
1
CCSD         1.8628
39
            1.2862
4
1.8164
25
1.7990
25
1.2796
4
1.2998
4
1.2836
4
     
CCSD=FULL         1.5748
7
            1.2853
4
1.2916
4
1.2785
4
1.2768
4
1.2939
4
1.2791
4
     
CCSD(T)         1.8690
40
      1.9004
1
    1.5351
7
1.8214
25
1.7949
22
1.4879
6
1.7899
21
1.6828
12
1.8539
1
1.7098
1
 
CCSD(T)=FULL         1.8331
27
            1.4770
6
1.8140
24
1.7926
15
1.4564
3
1.7628
18
1.3669
5
  1.7073
1
1.6932
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 1.8975
42
1.4346
6
1.8969
42
1.4305
6
1.9106
42
1.8960
42
density functional B1B95 1.9771
14
  1.9522
1
  1.9576
1
1.9504
1
B3LYP 1.9288
42
1.4495
6
1.9272
42
1.4447
6
1.9313
42
1.9198
42
Moller Plesset perturbation MP2 1.9308
42
1.4493
6
1.9285
42
1.4444
6
1.9380
42
1.9260
42
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.