return to home page

III.G.1.a.

Comparison of levels of theory for Mg-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 3.5278
2
PM3 2.3424
1
PM6 1.6514
3
composite G2 3.1933
3
G3 4.6852
3
G3B3 3.6449
3
CBS-Q 3.1933
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
hartree fock HF 2.4899
1		 3.2638
3		 3.1181
3		 3.2632
3		 2.8360
2		 3.1933
3		 3.1378
3		 4.6818
3		 3.5227
2		 3.1990
3		 6.7241
1		 4.6360
3		 3.5184
2		 3.5104
2		 3.4968
2		 3.4711
2		 3.4743
2		 3.8230
2
density functional LSDA 2.5658
2		 3.0700
3		 3.0161
3		 3.1730
3		 3.1504
3		 3.1504
3		 3.2794
3		 3.1481
3		 3.1481
3		 3.1322
3		     3.1533
3		 3.1445
3		 3.2447
2		 3.2844
3		 3.2213
2		 3.2194
2
SVWN   3.1155
3		     3.1505
3		   3.1628
3		                      
BLYP 2.5303
1		 3.7991
3		 3.4106
3		 3.8189
3		 3.7246
3		 3.7246
3		 3.5825
3		 3.6971
3		 3.6974
3		 3.6458
3		     3.6289
2		 3.5666
2		   3.8641
1		    
B1B95 2.6094
2		 3.4558
3		 3.2991
3		 3.5382
3		 3.4923
3		 3.4882
3		 3.6230
2		 3.4860
3		 3.4860
3		 3.4645
3		     3.4885
3		 3.4777
3		 3.3439
2		 3.4436
3		 3.3251
2		 3.3211
2
B3LYP 2.5140
1		 3.7625
3		 3.3644
3		 3.7512
3		 3.6449
3		 3.6449
3		 3.5678
3		 3.6290
3		 3.4802
2		 3.5874
3		 3.9018
1		 4.6148
3		 3.6366
3		 3.4511
2		 3.5991
3		 3.4080
2		 3.5766
3		 3.5795
3
B3LYPultrafine         3.6450
3		                          
B3PW91 2.5022
1		 3.5236
3		 3.2975
3		 3.5074
3		 3.4636
3		 3.4636
3		 3.4119
3		 3.4552
3		 3.3786
2		 3.4454
3		     3.3879
2		 3.3576
2		   3.6026
1		    
mPW1PW91 2.8170
2		 3.5077
3		 3.2562
2		 3.4917
3		 3.4480
3		 3.4480
3		 3.3994
3		 3.4411
3		 3.4416
3		 3.4345
3		     3.3708
2		 3.3453
2		   3.5905
1		    
M06-2X         3.3568
3		                          
PBEPBE 2.5118
1		 3.4481
3		 3.2564
2		 3.4297
2		 3.4373
3		 3.4373
3		 3.3734
3		 3.4247
3		 3.4247
3		 3.4167
3		 3.4923
1		   3.4333
3		 3.4123
3		 3.3452
2		     3.3160
2
PBEPBEultrafine         3.5001
1		                          
HSEh1PBE         3.2595
3		                          
Moller Plesset perturbation MP2FC 2.4869
1		 3.2506
3		 3.4939
3		 3.2394
3		 3.1059
3		 3.1059
3		 3.6908
3		 3.7123
3		 3.7123
3		 3.1052
3		   3.9952
3		 3.7866
3		 3.3530
2		 3.5831
3		 3.7241
3		 3.6041
3		 3.5739
3
MP2FU 2.4801
1		 3.2490
3		 3.2375
2		 3.5594
2		 3.6959
3		 3.6950
3		 3.0411
3		 3.6793
3		 3.3617
2		 3.2917
2		     3.3413
2		 3.2714
2		 3.4939
3		 4.4138
1		   3.2732
2
MP3         3.6410
3		                          
MP4   3.6151
2		     3.1043
3		     4.2287
1		 3.3208
2		         3.5271
3		        
B2PLYP         3.4965
3		   3.5330
3		                      
Configuration interaction CID   3.6289
2		 3.2367
2		 3.6319
2		 3.3434
2		     3.8329
3		                    
CISD   3.6219
2		 3.2436
2		 3.6220
2		 3.3496
2		     3.3494
2		                    
Quadratic configuration interaction QCISD   3.3080
3		 3.2371
2		 3.6401
2		 3.0939
3		 3.3434
2		 3.9448
3		 3.9581
3		 3.3441
2		 3.3732
2		     4.0207
3		 3.7487
3		        
QCISD(T)         3.3259
2		               3.3097
2		 3.3186
2		   3.3183
2		 3.3082
2		  
Coupled Cluster CCD   3.6463
2		 3.2314
2		 3.6610
2		 3.0845
3		 3.3393
2		 3.2937
2		 3.9420
3		 3.3420
2		 3.3655
2		     4.0098
3		 3.3373
2		   3.3422
2		 3.3301
2		  
CCSD         3.0941
3		     5.1750
1		                    
CCSD(T)         4.7609
1		 4.7609
1		   4.5354
1		     4.0177
1		   3.8558
3		 3.5661
3		   3.7238
3		 3.5580
3		  
CCSD(T)=FULL         3.3005
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 4.6373
3		 3.5080
2		 3.5771
2		 3.4862
2		 3.5513
2		 4.3517
3
density functional B1B95 3.8294
1		 3.7383
1		        
B3LYP 3.5506
2		 3.4848
2		 3.5189
2		 3.4547
2		 3.4872
2		 3.0435
2
Moller Plesset perturbation MP2FC 3.5792
2		 3.4061
2		 4.0876
3		 3.6747
3		 4.1139
3		 3.0119
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.