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III.G.1.a.

Comparison of levels of theory for Al-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 1.7777
3
PM3 1.8924
3
PM6 1.9482
3
composite G2 1.9803
3
G3 1.9803
3
G3B3 1.9747
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		                    
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		    
HSEh1PBE         1.9698
3		                    
Moller Plesset perturbation MP2FC 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		  
MP2FU 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		                    
MP4   2.0156
3		     1.9760
3		                    
B2PLYP         1.9727
3		   1.9721
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 MP2FC 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.