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III.G.1.a.

Comparison of levels of theory for N-Al


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 1.4913
3
PM3 1.7166
3
PM6 1.6380
4
composite G2 1.7679
4
G3 1.7679
4
G3B3 1.7425
4
G4 1.7364
4
CBS-Q 1.7685
4

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 1.6716
4
1.8788
4
1.8391
4
1.9173
4
1.7733
7
1.7679
4
1.7746
4
1.8287
4
1.8287
4
1.8041
4
1.8243
1
1.7717
4
1.7979
4
1.7633
4
1.8057
4
1.8873
4
1.7656
4
1.8072
4
1.8350
1
1.8219
1
1.8574
1
1.8238
1
ROHF 1.7663
1
1.8581
1
    1.7855
3
1.8275
1
1.8390
1
  1.8234
1
1.8151
1
    1.8529
1
1.8258
1
        1.8293
1
1.8179
1
1.8511
1
1.8198
1
density functional LSDA 1.7315
4
1.7465
4
1.7365
4
1.7804
4
1.7259
4
1.7259
4
1.7300
4
1.7230
4
1.7230
4
1.7127
4
    1.7846
4
1.7195
4
1.6963
1
1.7451
4
1.7028
3
1.6975
1
1.7722
1
1.7630
1
1.7908
1
1.7655
1
SVWN   1.7715
4
    1.8502
2
  1.7299
4
                             
BLYP 1.7617
4
1.8492
4
1.8098
4
1.8700
4
1.8030
4
1.8030
4
1.8083
4
1.8009
4
1.8009
4
1.7873
4
    1.8190
4
1.7960
4
        1.8044
1
1.7963
1
1.8231
1
1.7986
1
B1B95 1.6832
4
1.7586
4
1.7479
4
1.7975
4
1.7378
4
1.7379
4
1.7428
4
1.7352
4
1.7352
4
1.7256
4
    1.7556
4
1.7341
4
1.6871
2
1.7536
3
1.7147
3
1.6884
2
1.7966
1
1.7875
1
1.8174
1
1.7898
1
B3LYP 1.6917
4
1.7869
4
1.7511
4
1.8017
4
1.7425
4
1.7425
4
1.7484
4
1.7406
4
1.7406
4
1.7294
4
  1.7457
4
1.7588
4
1.7382
4
1.7252
3
1.7652
4
1.7397
4
1.7332
4
1.7981
1
1.7895
1
1.8182
1
1.7917
1
B3LYPultrafine         1.7227
3
                      1.7452
4
         
B3PW91 1.6862
4
1.7859
4
1.7498
4
1.7981
4
1.7390
4
1.7390
4
1.7434
4
1.7362
4
1.7362
4
1.7264
4
    1.7561
4
1.7342
4
        1.7967
1
1.7868
1
1.8172
1
1.7893
1
mPW1PW91 1.6828
4
1.7843
4
1.7489
4
1.7967
4
1.7395
4
1.7395
4
1.7442
4
1.7369
4
1.7369
4
1.7244
4
    1.7575
4
1.7355
4
        1.7966
1
1.7864
1
1.8175
1
1.7890
1
M06-2X         1.7378
4
                          1.8003
1
1.7955
1
1.8208
1
1.7985
1
PBEPBE 1.7516
4
1.8442
4
1.8046
4
1.8610
4
1.7947
4
1.7947
4
1.7990
4
1.7915
4
1.7915
4
1.7802
4
    1.8120
4
1.7877
4
1.7777
3
1.7038
1
1.7411
2
1.7785
3
1.7997
1
1.7900
1
1.8185
1
1.7920
1
PBEPBEultrafine         1.8035
1
                                 
PBE1PBE         1.7374
4
                                 
HSEh1PBE         1.7575
2
                          1.7976
1
1.7872
1
1.8185
1
1.7893
1
TPSSh         1.7563
4
  1.7607
4
            1.7538
4
               
Moller Plesset perturbation MP2 1.6699
4
1.7621
4
1.7217
4
1.7750
4
1.7242
4
1.7242
4
1.7286
4
1.7055
4
1.7055
4
1.6988
4
  1.7416
3
1.7423
4
1.7174
4
1.8144
1
1.7372
4
1.6842
3
1.8163
1
1.8303
1
1.8143
1
1.8500
1
1.8159
1
MP2=FULL 1.6704
4
1.7626
4
1.7218
4
1.7754
4
1.7236
4
1.7236
4
1.7277
4
1.7049
4
1.7049
4
1.6933
4
    1.7418
4
1.7126
4
1.7855
1
1.7639
2
1.6345
1
  1.8282
1
1.8076
1
1.8500
1
1.8115
1
ROMP2                                     1.8299
1
1.8177
1
1.8500
1
1.8196
1
MP3         1.7371
4
  1.7444
4
                      1.8320
1
1.8149
1
1.8528
1
1.8164
1
MP3=FULL         1.7438
4
  1.7486
4
                             
MP4 1.7618
1
1.7715
4
    1.7353
4
      1.7205
4
1.8178
1
      1.7541
3
        1.8351
1
1.8169
1
1.8553
1
1.8177
1
B2PLYP         1.7338
4
                1.7375
4
               
Configuration interaction CID 1.7574
1
1.7800
4
1.7456
4
1.7957
4
1.7400
4
  1.8374
1
1.7331
4
1.8199
1
1.8143
1
    1.8541
1
1.8214
1
               
CISD 1.7535
1
1.8182
3
1.7787
3
1.8333
3
1.7453
4
  1.8247
1
1.7412
4
1.8166
1
1.8109
1
    1.8510
1
1.8181
1
               
Quadratic configuration interaction QCISD 1.7541
1
1.8124
4
1.7755
4
1.8274
4
1.7597
4
1.7597
4
1.7644
4
1.7564
4
1.7564
4
1.7464
4
    1.7811
4
1.7476
4
        1.8235
1
1.8031
1
1.8437
1
1.8044
1
QCISD(T) 1.7563
1
      1.7676
4
      1.8122
1
1.8061
1
    1.7897
4
1.7555
4
  1.7794
3
1.7390
3
  1.8265
1
1.8046
1
1.8461
1
1.8061
1
Coupled Cluster CCD 1.7575
1
1.7789
4
1.7422
4
1.7942
4
1.7404
4
1.7404
4
1.7450
4
1.7300
4
1.7300
4
1.7215
4
    1.7620
4
1.7318
4
  1.7361
3
1.6805
2
  1.8323
1
1.8153
1
1.8530
1
1.8169
1
CCSD         1.7594
3
      1.8098
1
1.8038
1
    1.8447
1
1.8106
1
        1.8223
1
1.8033
1
1.8427
1
1.8048
1
CCSD(T) 1.7541
1
      1.7579
2
      1.8106
1
1.8046
1
    1.7763
4
1.7447
4
1.6764
1
1.8107
3
1.7478
4
  1.8246
1
1.8033
1
1.8442
1
1.8047
1
CCSD(T)=FULL         1.7735
3
              1.8455
1
1.8060
1
1.6577
1
1.8578
1
1.8050
1
  1.8243
1
1.7975
1
1.8451
1
1.8012
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 1.9123
4
1.7710
4
1.9060
4
1.7762
4
1.8831
4
1.8317
4
density functional B1B95 1.8743
1
1.8114
1
       
B3LYP 1.7978
4
1.7482
4
1.8020
4
1.7521
4
1.7887
4
1.7826
4
Moller Plesset perturbation MP2 1.7728
4
1.7265
4
1.7706
4
1.7271
4
1.7713
4
1.7655
4
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.