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III.G.1.a.

Comparison of levels of theory for N-Cl


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 1.6318
7
PM3 1.6551
9
PM6 1.6912
10
composite G2 1.7116
9
G3 1.7311
10
G3B3 1.7761
10
G4 1.7421
10
CBS-Q 1.7350
10

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 cc-pCVDZ cc-pCVTZ
hartree fock HF 1.8503
9
2.0062
10
1.8342
10
2.0703
10
1.7484
20
1.7311
10
1.7232
10
1.7451
10
1.7463
9
1.7155
9
1.8296
2
1.7365
10
1.7494
10
1.7172
10
1.7002
6
1.7344
10
1.7121
10
1.6337
4
1.6577
1
1.7242
8
1.6707
1
1.6392
1
ROHF 1.8079
3
1.8787
3
1.7858
3
1.8488
3
1.6989
3
1.6989
3
1.6785
3
1.7140
3
1.7140
3
1.6729
3
    1.7121
3
1.6688
3
1.6548
3
1.6805
3
1.6546
3
1.6467
3
1.6577
1
1.6389
1
  1.6392
1
density functional LSDA 1.8635
9
1.8428
9
1.7931
9
1.8654
9
1.7454
9
1.7454
9
1.7377
9
1.7552
9
1.7552
9
1.7207
9
    1.7541
9
1.7243
9
1.6002
3
1.7389
9
1.6640
7
1.5936
3
1.6136
1
1.5901
1
1.6304
1
1.5916
1
SVWN   1.8794
9
    1.7609
7
  1.7376
9
                             
BLYP 1.9122
9
1.9427
10
1.8664
10
1.9311
10
1.8201
10
1.8201
10
1.8117
10
1.8332
10
1.8337
9
1.7959
9
    1.8273
10
1.8005
10
  2.0191
2
    1.6652
1
1.6421
1
1.6813
1
1.6427
1
B1B95 1.8597
9
1.8169
10
1.7939
10
1.8657
10
1.7472
10
1.7488
10
1.7414
10
1.7592
10
1.7592
9
1.7282
9
    1.7598
10
1.7305
10
1.6082
4
1.7439
10
1.7000
6
1.6022
4
1.6260
1
1.6066
1
1.6403
1
1.6071
1
B3LYP 1.8772
9
1.9049
10
1.8219
10
1.8902
10
1.7761
10
1.7761
10
1.7680
10
1.7876
10
1.7281
7
1.7545
9
1.9399
2
1.7777
10
1.7863
10
1.7585
10
1.6536
5
1.7707
10
1.7522
10
1.6197
4
  1.7679
8
1.6606
1
1.6234
1
B3LYPultrafine         1.7760
10
  1.9469
2
            1.9539
2
    1.7401
10
         
B3PW91 1.8386
7
1.8888
10
1.8022
10
1.8733
10
1.7564
10
1.7564
10
1.7493
10
1.7662
10
1.7088
7
1.7360
9
    1.7673
10
1.7398
10
  1.9319
2
    1.6324
1
  1.6478
1
1.6123
1
mPW1PW91 1.8320
7
1.8797
10
1.7548
8
1.8640
10
1.7472
10
1.7230
9
1.7401
10
1.7566
10
1.7567
9
1.7273
9
    1.7328
9
1.7311
10
  1.9165
2
      1.6088
1
1.6438
1
1.6093
1
M06-2X         1.7373
9
                          1.6376
1
1.6160
1
1.6518
1
1.6169
1
PBEPBE 1.8569
7
1.9159
10
1.7901
8
1.8642
8
1.7870
10
1.7870
10
1.7793
10
1.7983
10
1.7991
9
1.7634
9
1.9620
2
  1.7949
10
1.7676
10
1.6246
4
1.7719
5
1.8224
6
1.6180
4
1.6419
1
1.6212
1
1.6577
1
1.6218
1
PBEPBEultrafine         1.9466
5
                                 
PBE1PBE         1.7449
10
                                 
HSEh1PBE         1.7654
8
                          1.6280
1
1.6081
1
1.6430
1
1.6086
1
TPSSh         1.7598
10
  1.7571
10
            1.7494
10
               
Moller Plesset perturbation MP2 1.8558
5
1.9498
10
1.8281
10
1.9310
10
1.7846
12
1.7520
10
1.8050
14
1.7605
10
1.7614
9
1.7356
9
  1.7547
10
1.7742
10
1.7683
12
1.6473
2
1.7659
10
1.6744
8
  1.6403
1
1.7471
8
1.6532
1
1.6255
1
MP2=FULL 1.8556
5
1.9229
9
1.7688
8
1.8779
8
1.7826
12
1.7498
10
1.7415
10
1.7585
10
1.6869
7
1.6629
7
    1.7729
10
1.7257
10
1.5541
1
1.8403
4
1.6153
5
  1.6385
1
1.7407
8
1.6516
1
 
ROMP2 1.8133
3
1.8524
3
1.7456
3
1.8220
3
1.6501
3
1.6501
3
1.6368
3
1.6533
3
1.6533
3
1.6253
3
    1.6660
3
1.6238
3
1.6077
3
1.6484
3
1.6129
3
1.6012
3
1.6383
1
1.6085
1
  1.6085
1
MP3         1.7392
10
  1.7430
10
                      1.6543
1
1.6260
1
  1.6256
1
MP3=FULL         1.7464
10
  1.7439
10
                             
MP4   1.9193
8
    1.7790
10
      1.7120
7
        1.7379
5
        1.6558
1
1.6259
1
1.6692
1
1.6255
1
B2PLYP         1.7691
9
                1.7435
10
               
B2PLYP=FULLultrafine         1.9585
2
                                 
Configuration interaction CID   1.9037
8
1.7535
8
1.8758
8
1.7273
10
    1.6929
8
                           
CISD   1.9117
7
1.7601
8
1.8929
7
1.7315
10
    1.6976
8
                           
Quadratic configuration interaction QCISD   1.9427
10
1.7939
8
1.9004
8
1.7565
10
1.7200
8
1.7389
9
1.7625
10
1.7622
9
1.6910
7
    1.7659
9
1.7259
9
        1.6590
1
1.6280
1
1.6731
1
1.6274
1
QCISD(T)   1.9303
1
    1.7608
9
1.7763
1
1.7719
1
1.7757
1
        1.7485
8
1.7098
8
  1.6993
5
1.6355
4
  1.6628
1
1.6316
1
1.6772
1
1.6313
1
Coupled Cluster CCD   1.9121
8
1.7718
8
1.8859
8
1.7422
10
1.7046
8
1.6975
8
1.7038
8
1.6963
7
1.6768
7
    1.7513
9
1.6846
8
  1.7042
7
1.6695
7
  1.6555
1
1.6258
1
1.6686
1
1.6254
1
CCSD   1.9151
1
    1.7524
10
1.7641
1
1.7598
1
1.7630
1
        1.7818
1
1.7526
1
               
CCSD(T)   1.9300
1
    1.8849
3
1.8844
2
1.7716
1
1.7752
1
        1.7460
8
1.7377
9
1.5425
2
1.6962
5
1.6315
4
1.4964
1
1.6606
1
1.6296
1
1.6749
1
1.6293
1
CCSD(T)=FULL         1.7045
4
                  1.5390
2
    1.4929
1
1.6585
1
1.6240
1
1.6730
1
1.6261
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 2.0863
10
1.7338
10
2.0963
10
1.7360
10
2.0721
10
2.0746
10
density functional B1B95 1.9764
2
1.9082
2
       
B3LYP 1.8859
10
1.7838
10
1.8826
10
1.7813
10
1.8847
10
1.8850
10
Moller Plesset perturbation MP2 1.9186
10
1.7643
10
1.9149
10
1.7624
10
1.8990
10
1.9046
10
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.