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III.G.1.a.

Comparison of levels of theory for C-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 1.7777
3
PM3 1.8924
3
PM6 1.9482
3
composite G2 1.9803
3
G3 1.9803
3
G3B3 1.9753
6
G4 1.9666
3
CBS-Q 1.9802
3

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) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ
hartree fock HF 1.8993
3
1.9977
3
1.9806
3
1.9921
3
1.9803
3
1.9787
3
1.9788
3
1.9753
3
1.9732
3
1.9704
3
1.9791
3
1.9829
3
1.9743
3
1.9801
3
1.9729
3
density functional SVWN   1.9710
3
    1.9513
3
  1.9510
3
               
BLYP 1.9300
3
2.0055
3
1.9903
3
1.9998
3
1.9876
3
1.9863
3
1.9881
3
1.9860
3
1.9845
3
1.9769
3
  1.9900
3
1.9837
3
   
B1B95 1.9088
3
1.9859
3
1.9712
3
1.9793
3
1.9672
3
1.9658
3
1.9666
3
1.9636
3
1.9620
3
    1.9699
3
     
B3LYP 1.9162
3
1.9933
3
1.9777
3
1.9867
3
1.9748
3
1.9734
3
1.9747
3
1.9723
3
1.9705
3
1.9646
3
1.9749
3
1.9772
3
1.9702
3
  1.9684
3
B3LYPultrafine 1.9163
3
      1.9748
3
                  1.9691
3
B3PW91 1.9129
3
1.9922
3
1.9771
3
1.9848
3
  1.9714
3
1.9722
3
1.9690
3
1.9672
3
1.9629
3
  1.9754
3
1.9672
3
   
mPW1PW91 1.9093
3
1.9894
3
1.9743
3
1.9818
3
1.9700
3
1.9685
3
1.9692
3
1.9659
3
1.9641
3
1.9601
3
  1.9725
3
1.9643
3
   
M06-2X         1.9637
3
                   
PBEPBE 1.9223
3
2.0000
3
1.9855
3
1.9931
3
1.9810
3
1.9795
3
1.9807
3
1.9777
3
1.9760
3
1.9709
3
  1.9839
3
1.9759
3
   
PBE1PBE         1.9699
3
                   
HSEh1PBE         1.9698
3
                   
TPSSh         1.9799
3
  1.9785
3
          1.9734
3
   
Moller Plesset perturbation MP2 1.9133
3
2.0100
3
1.9828
3
2.0051
3
1.9734
3
1.9718
3
1.9722
3
1.9676
3
1.9665
3
1.9634
3
1.9728
3
1.9818
3
  1.9825
3
 
MP2=FULL 1.9128
3
2.0092
3
1.9801
3
2.0041
3
1.9691
3
1.9676
3
1.9680
3
1.9649
3
1.9635
3
1.9522
3
  1.9789
3
     
MP3         1.9715
3
  1.9710
3
               
MP3=FULL         1.9684
3
  1.9671
3
               
MP4   2.0156
3
    1.9760
3
                   
B2PLYP         1.9727
3
              1.9685
3
   
Configuration interaction CID   2.0060
3
1.9800
3
2.0015
3
1.9704
3
    1.9651
3
             
CISD   2.0067
3
1.9805
3
2.0021
3
1.9709
3
    1.9656
3
             
Quadratic configuration interaction QCISD   2.0152
3
    1.9750
3
                   
QCISD(T)         1.9767
3
                   
Coupled Cluster CCD   2.0135
3
    1.9736
3
                   
CCSD         1.9745
3
                   
CCSD(T)         1.9765
3
                   

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 1.9855
3
1.9838
3
1.9848
3
1.9797
3
1.9890
3
1.9791
3
density functional B1B95 1.9829
3
1.9810
3
1.9824
3
1.9761
3
1.9821
3
1.9678
3
B3LYP 1.9849
3
1.9830
3
1.9839
3
1.9792
3
1.9853
3
1.9750
3
Moller Plesset perturbation MP2 2.0049
3
1.9797
3
2.0004
3
1.9727
3
2.0086
3
1.9944
3
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.