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III.G.1.a.

Comparison of levels of theory for Cl-C


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 1.7064
39
PM3 1.7336
122
PM6 1.7462
151
composite G2 1.7657
116
G3 1.7639
149
G3B3 1.7857
163
G4 1.7767
155
CBS-Q 1.7645
129

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 aug-cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ Sadlej_pVTZ
hartree fock HF 1.8112
155
1.8516
155
1.7770
155
1.8345
155
1.7689
358
1.7639
155
1.7661
155
1.7660
155
1.7660
149
1.7619
149
1.7621
95
1.7614
167
1.7699
155
1.7609
151
1.7271
36
1.7713
138
1.7619
132
1.7243
28
1.7836
1
1.7315
56
1.7752
3
1.7823
1
  1.7713
11
ROHF 1.7664
10
1.8374
33
1.7598
33
1.8210
29
1.7434
33
1.7434
33
1.7406
33
1.7445
33
1.7494
29
1.6895
10
  1.6948
1
1.7497
33
1.7400
33
1.7266
18
1.7402
18
1.7293
18
1.7253
18
           
density functional LSDA 1.8302
149
1.8208
149
1.7719
149
1.8288
149
1.7601
149
1.7612
146
1.7576
149
1.7580
149
1.7582
149
1.7517
136
  1.7455
15
1.7612
149
1.7492
149
1.6909
9
1.7609
129
1.7363
30
1.6881
9
1.7627
1
1.7441
5
1.7637
3
1.7709
1
1.7616
1
 
SVWN   1.8202
130
    1.7605
127
1.7444
15
1.7499
130
1.7424
15
1.7424
15
1.7342
15
    1.7460
15
1.7339
15
  1.7526
12
1.7409
12
    1.7441
5
1.7637
3
     
BLYP 1.8744
155
1.9005
156
1.8233
136
1.8861
156
1.8123
156
1.8125
156
1.8101
156
1.8086
136
1.8127
150
1.8037
150
  1.7953
15
1.8134
156
1.8036
156
  1.8279
86
    1.8164
1
1.7973
5
1.8199
3
1.8247
1
1.8177
1
 
B1B95 1.8322
149
1.8254
149
1.7794
149
1.8358
149
1.7674
142
1.7660
149
1.7639
149
1.7652
149
1.7653
149
1.7592
149
  1.7513
15
1.7679
149
1.7575
149
1.6747
11
1.7684
129
1.7564
31
1.6732
11
1.7718
1
1.7510
5
1.7720
3
1.7794
1
1.7731
1
 
B3LYP 1.8489
155
1.8721
155
1.7999
155
1.8580
155
1.7870
155
1.7871
155
1.7851
155
1.7870
155
1.7696
64
1.7800
152
1.7841
88
1.7785
167
1.7895
155
1.7792
153
1.7417
28
1.7793
88
1.7665
75
1.7402
28
1.7954
1
1.7460
56
1.7953
3
1.8036
1
1.7962
1
1.7936
11
B3LYPultrafine         1.7867
146
  1.7844
31
        1.8097
3
1.7806
12
1.7822
61
  1.7799
12
1.7760
150
    1.7397
2
       
B3PW91 1.8340
71
1.8571
153
1.7864
153
1.8428
153
1.7737
153
1.7737
153
1.7677
132
1.7721
153
1.7545
62
1.7663
147
  1.7596
15
1.7753
153
1.7658
153
  1.7892
86
    1.7806
1
1.7595
5
1.7814
3
1.7887
1
1.7807
1
 
mPW1PW91 1.8269
74
1.8505
155
1.7647
78
1.8365
155
1.7679
155
1.7680
155
1.7656
154
1.7668
155
1.7667
149
1.7612
149
  1.7547
15
1.7700
155
1.7532
103
  1.7819
109
1.7658
20
  1.7755
1
1.7543
5
1.7761
3
1.7842
1
1.7759
1
 
M06-2X 1.8262
29
1.8362
29
1.7708
29
1.8205
29
1.7539
144
1.7627
29
1.7611
29
1.7620
29
1.7621
29
1.7583
29
  1.7554
15
1.7651
29
1.7567
29
  1.7644
15
1.7532
12
  1.7790
1
1.7559
5
1.7769
3
1.7858
1
1.7794
1
 
PBEPBE 1.8509
73
1.8742
149
1.7909
61
1.8443
61
1.7874
149
1.7875
149
1.7851
149
1.7865
149
1.7868
149
1.7788
146
1.7827
87
1.7727
15
1.7830
145
1.7784
147
1.6962
11
1.7926
23
1.7784
58
1.6943
11
1.7912
1
1.7553
7
1.7949
3
1.7978
1
1.7914
1
1.7946
11
PBEPBEultrafine         1.7938
152
            1.8102
3
1.7799
12
1.7698
12
  1.7791
12
1.7698
12
    1.7409
2
       
PBE1PBE 1.8148
15
1.7603
15
1.7603
15
1.8143
15
1.7593
145
1.7493
15
1.7487
15
1.7487
15
1.7487
15
1.7428
15
  1.7529
15
1.7517
15
1.7428
15
  1.7594
12
1.7506
12
    1.7740
3
1.7742
3
     
HSEh1PBE 1.8355
29
1.8410
29
1.7713
29
1.8250
29
1.7601
140
1.7617
29
1.7598
29
1.7609
29
1.7609
29
1.7567
29
  1.7540
15
1.7644
29
1.7559
29
  1.7630
15
1.7534
14
  1.7745
1
1.7538
5
1.7755
3
1.7824
1
1.7751
1
 
TPSSh   1.8764
3
1.8199
3
1.8699
3
1.7615
163
1.8028
3
1.7600
162
1.8015
3
      1.8059
3
1.8049
3
1.7555
162
  1.8039
3
1.7952
3
    1.7909
3
1.7909
3
     
Moller Plesset perturbation MP2 1.8315
73
1.8815
155
1.7899
155
1.8637
155
1.7687
192
1.7597
152
1.7685
310
1.7601
154
1.7588
149
1.7391
92
  1.7598
167
1.7707
155
1.7603
153
1.7401
10
1.7675
85
1.7321
31
1.7100
8
1.7765
1
1.7265
53
1.7745
3
1.7833
1
1.7745
1
1.7846
11
MP2=FULL 1.8325
67
1.8770
103
1.7758
75
1.8490
75
1.7640
192
1.7556
135
1.7534
135
1.7589
155
1.7414
64
1.7286
58
  1.7534
15
1.7634
103
1.7463
112
1.7348
10
1.7635
33
1.7379
22
1.7144
7
1.7741
1
1.7226
56
1.7637
3
1.7811
1
1.7707
1
 
ROMP2 1.8154
13
1.8298
16
1.7682
13
1.8432
13
1.7222
16
1.7222
16
1.7158
16
1.7198
16
1.7215
13
1.7176
13
  1.6750
1
1.7340
16
1.7142
16
1.6816
10
1.7358
13
1.6866
10
1.5735
4
  1.7759
3
1.7745
3
     
MP3         1.7667
142
  1.7489
166
        1.7925
3
1.7979
3
1.7831
3
          1.7797
3
1.7783
3
     
MP3=FULL         1.7495
162
  1.7448
148
        1.7913
3
1.7963
3
1.7772
3
          1.7731
3
1.7685
3
     
MP4 1.8517
6
1.8847
74
    1.7555
94
    1.7317
2
1.7574
54
    1.7747
12
1.7777
12
1.7624
36
  1.7825
12
1.7466
8
  1.7866
1
1.7403
2
  1.7936
1
1.7850
1
 
MP4=FULL   1.8900
12
    1.7650
12
      1.7652
12
      1.7760
12
1.7580
12
  1.7756
11
1.7442
8
             
B2PLYP 1.8580
3
1.8813
3
1.8148
3
1.8738
3
1.7683
114
1.7961
3
1.7964
3
1.7964
3
1.7963
3
1.7901
3
  1.8013
3
1.8023
3
1.7544
139
  1.8034
3
1.7914
3
    1.7872
3
1.7873
3
     
B2PLYP=FULL 1.8579
3
1.8813
3
1.8146
3
1.8737
3
1.7955
3
1.7955
3
1.7958
3
1.7959
3
1.7958
3
1.7876
3
  1.8008
3
1.8018
3
1.7896
3
  1.8027
3
1.7886
3
    1.7849
3
1.7839
3
     
B2PLYP=FULLultrafine         1.7944
85
                                     
Configuration interaction CID   1.8566
71
1.7700
68
1.8393
68
1.7552
136
    1.7438
76
                      1.7476
5
1.7669
3
     
CISD 1.8400
6
1.8603
68
1.7714
68
1.8423
68
1.7564
133
    1.7453
71
                      1.7482
5
1.7673
3
     
Quadratic configuration interaction QCISD 1.8512
6
1.8848
144
1.7832
74
1.8594
75
1.7637
109
1.7529
75
1.7515
81
1.7636
100
1.7600
106
1.7403
53
  1.7614
15
1.7670
72
1.7458
56
  1.7894
25
1.7682
21
  1.7854
1
1.7466
7
1.7798
3
1.7926
1
1.7826
1
 
QCISD(T)         1.7560
67
    1.7663
6
      1.7660
15
1.7745
52
1.7461
43
  1.7579
24
1.7276
13
    1.7666
5
1.7853
3
1.7958
1
1.7860
1
 
Coupled Cluster CCD 1.8497
6
1.8676
75
1.7771
69
1.8489
69
1.7618
142
1.7487
75
1.7489
76
1.7491
81
1.7458
56
1.7422
50
  1.7583
15
1.7624
72
1.7500
50
1.6759
2
1.7649
38
1.7499
27
1.6757
2
1.7815
1
1.7587
5
1.7775
3
1.7891
1
1.7798
1
 
CCSD         1.7460
90
    1.7293
2
      1.7686
12
1.7728
36
1.7589
33
1.7173
5
1.7754
12
1.7457
8
1.7115
3
  1.7601
5
1.7789
3
     
CCSD=FULL         1.7593
12
            1.7673
12
1.7702
12
1.7516
12
1.7128
5
1.7735
12
1.7156
5
1.6957
4
  1.7734
3
1.7686
3
     
CCSD(T)   1.8327
2
    1.7589
94
1.7446
7
1.7195
2
1.7340
2
1.7185
2
  1.6531
1
1.7653
15
1.7728
49
1.7391
52
1.7741
7
1.7736
36
1.7500
20
1.7148
3
1.7884
1
1.7569
5
1.7848
3
1.7955
1
1.7858
1
 
CCSD(T)=FULL         1.7713
45
            1.7680
11
1.7815
38
1.7586
25
1.7632
7
1.7915
22
1.7608
9
1.7310
4
1.7864
1
1.7789
3
  1.7933
1
1.7097
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 1.8358
155
1.7740
148
1.8345
155
1.7738
148
1.8307
155
1.8368
155
density functional B1B95 1.8508
95
1.7883
92
       
B3LYP 1.8684
155
1.8023
148
1.8656
155
1.8008
148
1.8545
155
1.8576
155
Moller Plesset perturbation MP2 1.8689
155
1.7783
148
1.8672
155
1.7767
148
1.8618
155
1.8713
155
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.