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III.G.1.a.

Comparison of levels of theory for Si-S


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 1.8551
2
PM3 1.7948
3
PM6 1.8972
3
composite G2 1.9515
3
G3 1.9515
3
G3B3 1.9821
3
CBS-Q 1.9515
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) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(T+d)Z
hartree fock HF 1.9111
3		 2.0579
3		 1.9419
3		 2.0641
3		 1.9515
3		 1.9515
3		 1.9503
3		 1.9485
3		 1.9485
3		 1.9482
3		 1.9102
1		 1.9577
3		 1.9665
3		 1.9530
3		 1.9459
3		 1.9695
3		 1.9515
3		 1.9449
3		 1.9108
1
density functional LSDA 1.9411
3		 1.9890
3		 1.9612
3		 2.0619
3		 1.9736
3		 1.9736
3		 1.9708
3		 1.9677
3		 1.9677
3		 1.9634
3		     1.9853
3		 1.9655
3		 1.9698
2		 1.9824
3		 1.9727
2		 1.9115
1		  
SVWN   2.0519
3		     1.9359
2		   1.9708
3		                        
BLYP 1.9650
3		 2.0862
3		 1.9904
3		 2.0968
3		 2.0054
3		 2.0054
3		 2.0026
3		 2.0016
3		 2.0016
3		 1.9949
3		     2.0157
3		 1.9971
3		   1.9842
1		      
B1B95 1.9322
3		 1.9818
3		 1.9546
3		 2.0565
3		 1.9641
3		 1.9650
3		 1.9627
3		 1.9618
3		 1.9618
3		 1.9596
3		     1.9782
3		 1.9616
3		 1.9684
2		 1.9762
3		 2.0244
1		 1.9643
2		  
B3LYP 1.9447
3		 2.0653
3		 1.9691
3		 2.0752
3		 1.9821
3		 1.9821
3		 1.9799
3		 1.9782
3		 1.9938
2		 1.9734
3		 1.9384
1		 1.9832
3		 1.9934
3		 1.9760
3		 1.9687
3		 1.9921
3		 1.9729
3		 1.9660
3		 1.9380
1
B3LYPultrafine         1.9822
3		                            
B3PW91 1.9570
2		 2.0573
3		 1.9623
3		 2.0646
3		 1.9725
3		 1.9725
3		 1.9702
3		 1.9686
3		 1.9829
2		 1.9653
3		     1.9850
3		 1.9682
3		   1.9571
1		      
mPW1PW91 1.9522
2		 2.0528
3		 1.9711
2		 2.0600
3		 1.9675
3		 1.9675
3		 1.9654
3		 1.9640
3		 1.9640
3		 1.9608
3		     1.9802
3		 1.9640
3		   1.9528
1		      
M06-2X         1.9610
3		                            
PBEPBE 1.9716
2		 2.0736
3		 1.9925
2		 2.0984
2		 1.9912
3		 1.9912
3		 1.9885
3		 1.9879
3		 1.9879
3		 1.9828
3		 1.9516
1		   2.0027
3		 1.9853
3		 1.9913
2		   1.9579
1		 1.9864
2		 1.9509
1
PBEPBEultrafine         1.9645
1		                            
HSEh1PBE         1.9696
3		                            
Moller Plesset perturbation MP2FC 1.9134
2		 2.0610
3		 1.9504
3		 2.0685
3		 1.9601
3		 1.9601
3		 1.9583
3		 1.9567
3		 1.9567
3		 1.9620
3		   1.9672
3		 1.9813
3		 1.9648
3		 1.9552
3		 1.9870
3		 1.9637
3		 1.9839
2		 1.9418
1
MP2FU 1.9129
2		 2.0615
3		 1.9571
2		 2.0718
2		 1.9582
3		 1.9582
3		 1.9563
3		 1.9566
3		 1.9654
2		 1.9633
2		     1.9796
3		 1.9687
2		 1.9506
3		 1.9713
1		   1.9556
2		 1.9352
1
MP3         1.9562
3		                            
MP4   2.0884
2		     1.9785
3		     1.9573
1		 1.9835
2		         1.9800
3		          
B2PLYP         1.9778
3		   1.9758
3		                        
Configuration interaction CID   2.0793
2		 1.9589
2		 2.0864
2		 1.9553
3		     1.9512
3		                      
CISD   2.0935
2		 1.9649
2		 2.1002
2		 1.9613
3		     1.9719
2		                      
Quadratic configuration interaction QCISD   2.1038
3		 1.9800
2		 2.1312
2		 1.9776
3		 1.9930
2		 1.9753
3		 1.9724
3		 1.9724
3		 1.9904
2		     1.9996
3		 1.9767
3		         1.9381
1
QCISD(T)         1.9843
3		     1.9495
1		         2.0242
2		 1.9999
2		   2.0274
2		 1.9979
2		    
Coupled Cluster CCD   2.0793
2		 1.9619
2		 2.0866
2		 1.9588
3		 1.9720
2		 1.9692
2		 1.9548
3		 1.9689
2		 1.9746
2		     1.9814
3		 1.9776
2		   2.0004
2		 1.9754
2		    
CCSD         1.9695
3		     1.9332
1		                      
CCSD(T)   2.0570
1		     1.9515
1		 1.9515
1		 1.9515
1		 1.9458
1		 1.9458
1		   1.9451
1		   2.0028
3		 1.9814
3		   2.0076
3		 1.9805
3		   1.9464
1
CCSD(T)=FULL         1.9908
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 2.0768
3		 1.9655
3		 2.0747
3		 1.9638
3		 2.0355
3		 2.0589
3
density functional B1B95 2.0507
1		 1.9655
1		        
B3LYP 2.0960
3		 1.9978
3		 2.0935
3		 1.9971
3		 2.0661
3		 2.0702
3
Moller Plesset perturbation MP2FC 2.0778
3		 1.9819
3		 2.0797
3		 1.9757
3		 2.0504
3		 2.0609
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.