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III.G.1.a.

Comparison of levels of theory for H-Li


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 1.7069
3
PM3 1.8042
3
PM6 1.9799
3
composite G2 1.9167
3
G3 1.9167
3
G3B3 1.8888
3
CBS-Q 1.9167
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-pCVDZ cc-pCVTZ
hartree fock HF 1.6737
3		 1.9179
3		 1.9179
3		 1.9600
3		 1.9167
3		 1.9064
3		 1.8816
3		 1.8509
3		 1.8432
3		 1.9001
3		 1.6076
1		 1.8588
6		 1.8786
3		 1.8471
3		 1.8411
3		 1.8752
3		 1.8366
3		 1.8338
3		 1.8754
3		 1.8454
3
ROHF         2.0572
2		                              
density functional LSDA 1.6932
3		 1.8965
3		 1.8965
3		 1.9250
3		 1.8940
3		 1.8870
3		 1.8682
3		 1.8335
3		 1.8295
3		 1.8765
3		     1.8693
3		 1.8295
3		 1.6913
1		 1.8541
3		 1.6735
1		 1.6696
1		    
SVWN   1.8953
6		     1.8762
6		   1.8621
6		                          
BLYP 1.7114
3		 1.8971
3		 1.8971
3		 1.9287
3		 1.8980
3		 1.8900
3		 1.8706
3		 1.8442
3		 1.8385
3		 1.8838
3		     2.0014
2		 1.9600
2		   1.6078
1		        
B1B95 1.7040
3		 1.9139
3		 1.9139
3		 1.9516
3		 1.9151
3		 2.0477
2		 1.8849
3		 1.8555
3		 1.8497
3		 1.9000
3		     1.8821
3		 1.8516
3		 1.9691
2		 1.6485
2		 1.9622
2		 1.9562
2		    
B3LYP 1.6962
3		 1.8887
3		 1.8887
3		 1.9214
3		 1.8888
3		 1.8805
3		 1.8612
3		 1.8319
3		 1.8264
3		 1.8742
3		 1.5905
1		 1.8449
6		 1.8603
3		 1.8275
3		 1.8186
3		 1.9769
2		 1.8173
3		 1.8113
3		 1.8551
3		 1.8255
3
B3LYPultrafine         1.8887
3		                              
B3PW91 1.7031
3		 1.9161
3		 1.9161
3		 1.9504
3		 1.9133
3		 1.9050
3		 1.8849
3		 1.8515
3		 1.8453
3		 1.8987
3		     2.0163
2		 1.9729
2		   1.6115
1		        
mPW1PW91 1.6998
3		 1.9093
3		 1.9094
3		 1.9443
3		 1.9081
3		 1.8999
3		 1.8802
3		 1.8467
3		 1.8404
3		 1.8934
3		     2.0090
2		 1.9661
2		   1.6115
1		        
M06-2X         1.8959
6		                              
PBEPBE 1.7143
3		 1.9117
3		 2.0438
2		 2.0921
2		 1.9110
3		 1.9035
3		 1.8846
3		 1.8553
3		 1.8489
3		 1.8966
3		 1.6049
1		   1.8834
3		 1.8507
3		 1.9585
2		     1.9481
2		    
PBEPBEultrafine         1.6374
1		                              
HSEh1PBE         1.9031
3		                              
Moller Plesset perturbation MP2FC 1.6843
3		 1.9257
3		 1.9257
3		 1.9672
3		 1.9165
3		 1.8990
3		 1.8765
3		 1.8473
3		 1.8344
3		 1.8941
3		   1.8536
6		 1.8737
3		 1.8415
3		 1.8362
3		 1.8750
3		 1.8348
3		 1.8316
3		 1.8688
3		 1.8398
3
MP2FU 1.7630
2		 1.9253
3		 2.0619
2		 2.1243
2		 1.9160
3		 1.8971
3		 1.8745
3		 1.8441
3		 1.8290
3		 2.0196
2		     1.8708
3		 1.8264
3		 1.8076
3		 1.8434
3		 1.8057
3		 1.7845
3		 1.8642
3		 1.8290
3
MP3         1.7038
2		                              
MP4   1.9347
3		     1.9214
3		     1.6128
1		 1.9506
2		         1.8438
3		            
B2PLYP         1.8758
6		   1.8574
6		                          
Configuration interaction CID   2.0710
2		 2.0710
2		 2.1319
2		 1.9225
3		     1.8523
3		                        
CISD   1.9398
3		 2.0730
2		 2.1342
2		 1.9248
3		     1.9723
2		                        
Quadratic configuration interaction QCISD   1.9398
3		 1.9393
3		 2.1342
2		 1.9248
3		 1.9023
3		 1.8803
3		 1.8542
3		 1.8349
3		 2.0289
2		     1.8754
3		 1.8451
3		            
QCISD(T)         1.9250
3		 1.6300
1		 1.6286
1		 1.6177
1		         2.0040
2		 1.9640
2		   2.0072
2		 1.9537
2		      
Coupled Cluster CCD   1.9371
3		 2.0710
2		 2.1319
2		 1.9225
3		 1.9002
3		 1.8783
3		 1.8523
3		 1.9509
2		 2.0275
2		     1.8737
3		 1.9627
2		   2.0062
2		 1.9528
2		      
CCSD         2.0008
2		 1.6300
1		 1.6286
1		 1.6177
1		                        
CCSD(T)   1.6731
1		     1.9250
3		 1.6300
1		 1.6286
1		 1.6177
1		 1.5999
1		   1.6102
1		   1.8755
3		 1.8454
3		 1.8412
3		 1.8797
3		 1.8392
3		 1.8361
3		 1.8696
3		 1.8436
3
CCSD(T)=FULL         1.9232
3		               1.8727
3		 1.8288
3		 1.8085
3		 1.9408
2		 1.8781
2		 1.7818
3		 1.8651
3		 1.8319
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 2.1150
2		 2.0471
2		 2.0802
2		 1.9984
2		 2.0650
2		 2.0605
2
density functional B1B95 1.6648
1		 1.6459
1		        
B3LYP 2.1066
2		 2.0470
2		 2.0964
2		 2.0212
2		 2.0284
2		 2.0223
2
Moller Plesset perturbation MP2FC 2.1224
2		 2.0507
2		 2.0833
2		 1.9954
2		 2.0726
2		 2.0664
2
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.