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III.G.1.a.

Comparison of levels of theory for F-Mg


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 2.3851
4
PM3 1.7607
5
PM6 1.8348
5
composite G2 1.7317
5
G3 1.7317
5
G3B3 1.7465
5
G4 1.7453
5
CBS-Q 1.7449
5

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 1.6906
5
1.7275
5
1.7084
5
1.7632
5
1.8551
7
1.7317
5
1.7534
5
1.7571
5
1.7571
5
1.7337
5
1.7443
1
1.7614
5
1.7503
5
1.7424
5
1.7366
5
1.7465
4
1.7417
5
1.7364
5
ROHF   1.7294
1
1.7119
1
  1.7356
1
1.7356
1
1.7604
1
1.7631
1
1.7631
1
                 
density functional LSDA 1.7010
5
1.7169
5
1.7111
5
1.7740
5
1.7367
5
1.7367
5
1.7680
5
1.7648
5
1.7648
5
1.7374
5
  1.7559
2
1.7548
5
1.7515
5
1.7524
2
1.7595
5
1.7514
4
1.7530
2
SVWN   1.7419
5
    1.7366
5
1.7269
2
1.7679
5
1.7531
2
1.7531
2
1.7301
2
    1.7446
2
1.7420
2
  1.7479
2
1.7421
2
 
BLYP 1.7254
5
1.7681
5
1.7336
5
1.8005
5
1.7634
5
1.7634
5
1.7998
5
1.7920
5
1.7918
5
1.7644
5
  1.7852
2
1.7780
4
1.7810
4
  1.7970
1
   
B1B95 1.7081
5
1.7235
5
1.7184
5
1.7793
5
1.7447
5
1.7452
5
1.7751
5
1.7725
5
1.7725
5
1.7471
5
  1.7619
2
1.7618
5
1.7600
5
1.7625
2
1.8460
1
1.7608
4
1.8277
1
B3LYP 1.7121
5
1.7491
5
1.7201
5
1.7826
5
1.7478
5
1.7478
5
1.7804
5
1.7758
5
1.7743
4
1.7495
5
1.7697
1
1.7852
5
1.7644
5
1.7636
4
1.7608
5
1.7709
4
1.7682
5
1.7616
5
B3LYPultrafine         1.7473
5
              1.7525
2
1.7536
2
  1.7586
2
1.7437
4
 
B3PW91 1.7129
4
1.7506
5
1.7231
5
1.7830
5
1.7482
5
1.7482
5
1.7782
5
1.7762
5
1.7748
4
1.7497
5
  1.7666
2
1.7647
4
1.7623
4
  1.7757
1
   
mPW1PW91 1.7094
4
1.7456
5
1.7186
4
1.7788
5
1.7445
5
1.7445
5
1.7742
5
1.7724
5
1.7725
5
1.7461
5
  1.7627
2
1.7613
4
1.7583
4
  1.7603
3
1.7507
2
 
M06-2X 1.6798
2
1.7304
2
1.7049
2
1.7574
2
1.7375
5
1.7280
2
1.7514
2
1.7510
2
1.7510
2
1.7321
2
  1.7532
2
1.7430
2
1.7414
2
  1.7465
2
1.7420
2
 
PBEPBE 1.7230
4
1.7663
5
1.7324
4
1.7972
4
1.7610
5
1.7610
5
1.7950
5
1.7889
5
1.7889
5
1.7622
5
1.7829
1
1.7811
2
1.7783
5
1.7778
5
1.7818
2
1.7726
2
1.7692
2
1.7843
2
PBEPBEultrafine         1.7546
3
              1.7663
2
1.7664
2
  1.7723
2
1.7690
2
 
PBE1PBE 1.6843
2
1.7102
2
1.7102
2
1.7672
2
1.7446
5
1.7349
2
1.7609
2
1.7599
2
1.7599
2
1.7386
2
  1.7624
2
1.7518
2
1.7495
2
  1.7546
2
1.7507
2
 
HSEh1PBE 1.6844
2
1.7392
2
1.7102
2
1.7672
2
1.7447
5
1.7349
2
1.7610
2
1.7600
2
1.7600
2
1.7386
2
  1.7628
2
1.7515
2
1.7499
2
  1.7547
2
1.7512
2
 
TPSSh         1.7444
5
  1.7623
5
            1.7535
5
       
Moller Plesset perturbation MP2 1.6955
4
1.7459
5
1.7227
5
1.7875
5
1.7552
5
1.7552
5
1.7910
5
1.7775
5
1.7775
5
1.7592
5
  1.7920
5
1.7711
5
1.7680
4
1.7671
5
1.7841
5
1.7771
5
1.7707
5
MP2=FULL 1.6981
4
1.7469
5
1.7230
4
1.7876
4
1.7531
5
1.7531
5
1.7874
5
1.7777
5
1.7766
4
1.7529
4
  1.7741
2
1.7705
4
1.7617
4
1.7573
5
1.7746
3
1.7538
2
1.7480
4
MP3         1.7477
5
  1.7416
5
                     
MP3=FULL         1.7397
5
  1.7577
5
                     
MP4   1.7519
4
    1.7579
5
    1.7841
1
1.7792
4
    1.7752
2
1.7635
2
1.7694
5
  1.7761
2
1.7694
2
 
MP4=FULL   1.7458
2
    1.7462
2
      1.7684
2
      1.7635
2
1.7533
2
  1.7717
2
1.7544
2
 
B2PLYP         1.7545
3
                1.7553
3
       
Configuration interaction CID   1.7395
4
1.7164
4
1.7791
4
1.7469
5
    1.7683
5
                   
CISD   1.7419
4
1.7184
4
1.7811
4
1.7483
5
    1.7682
4
                   
Quadratic configuration interaction QCISD   1.7474
5
1.7224
4
1.7874
4
1.7539
5
1.7532
4
1.7865
5
1.7756
5
1.7756
5
1.7548
4
  1.7693
2
1.7700
5
1.7631
5
  1.7684
2
1.7599
2
 
QCISD(T)         1.7543
5
    1.7819
1
      1.7716
2
1.7700
4
1.7643
4
  1.7799
4
1.7721
4
 
Coupled Cluster CCD   1.7416
4
1.7179
4
1.7822
4
1.7499
5
1.7492
4
1.7799
4
1.7717
5
1.7705
4
1.7511
4
  1.7663
2
1.7659
5
1.7593
4
  1.7731
4
1.7644
4
 
CCSD         1.7516
5
    1.7786
1
      1.7679
2
1.7579
2
1.7533
2
1.7498
2
1.7661
2
1.7581
2
1.7519
2
CCSD=FULL         1.7404
2
            1.7673
2
1.7579
2
1.7463
2
1.7409
2
1.7617
2
1.7439
2
1.7258
2
CCSD(T)         1.7490
3
1.7567
1
  1.7812
1
    1.7710
1
1.7711
2
1.7695
4
1.7637
4
1.7541
2
1.7792
4
1.7713
4
1.7568
2
CCSD(T)=FULL         1.7508
4
            1.7704
2
1.7603
2
1.7492
2
1.7447
2
1.7654
2
1.7483
2
1.7300
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 1.8249
5
1.7699
5
1.7748
5
1.7414
5
1.7658
5
1.7903
5
density functional B1B95 1.8400
1
1.7951
1
       
B3LYP 1.8296
5
1.7820
5
1.8001
5
1.7653
5
1.7732
5
1.8113
5
Moller Plesset perturbation MP2 1.8476
5
1.7991
5
1.8070
5
1.7728
5
1.7860
5
1.8227
5
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.