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III.G.1.a.

Comparison of levels of theory for Mg-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 2.8392
1
PM3 2.1095
2
PM6 2.0153
3
composite G2 2.2058
3
G3 2.2058
3
G3B3 2.2236
3
CBS-Q 2.2058
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 2.1073
2		 2.3044
3		 2.2042
3		 2.3377
3		 2.2058
3		 2.2058
3		 2.2083
3		 2.2062
3		 2.2063
3		 2.1925
3		 2.1344
1		 2.2571
3		 2.2039
3		 2.2221
2		 2.1927
3		 2.2433
2		 2.1970
3		 2.1939
3		 2.1376
1
ROHF         2.2516
1		                            
density functional LSDA 2.0531
3		 2.2183
3		 2.1998
3		 2.2579
3		 2.2016
3		 2.2016
3		 2.2035
3		 2.2011
3		 2.2011
3		 2.1859
3		     2.2030
3		 2.1876
3		 2.2004
1		 2.2108
3		 2.2188
2		 2.2010
1		  
SVWN   2.2612
3		     2.1788
2		   2.2036
3		                        
BLYP 2.1280
2		 2.2984
3		 2.2387
3		 2.3018
3		 2.2446
3		 2.2446
3		 2.2475
3		 2.2464
3		 2.2465
3		 2.2294
3		     2.2754
2		 2.2635
2		   2.1891
1		      
B1B95 2.0628
3		 2.2268
3		 2.2098
3		 2.2706
3		 2.2104
3		 2.2111
3		 2.2125
3		 2.2113
3		 2.2113
3		 2.1978
3		     2.2121
3		 2.1976
3		 2.2260
2		 2.2191
3		 2.2294
2		 2.2259
2		  
B3LYP 2.0758
3		 2.2820
3		 2.2193
3		 2.2839
3		 2.2236
3		 2.2236
3		 2.2260
3		 2.2249
3		 2.2558
2		 2.2091
3		 2.1492
1		 2.2492
3		 2.2231
3		 2.2114
3		 2.2095
3		 2.2631
2		 2.2135
3		 2.2099
3		 2.1502
1
B3LYPultrafine         2.2238
3		                            
B3PW91 2.1056
2		 2.2786
3		 2.2153
3		 2.2754
3		 2.2143
3		 2.2143
3		 2.2158
3		 2.2144
3		 2.2447
2		 2.2006
3		     2.2454
2		 2.2316
2		   2.1615
1		      
mPW1PW91 2.0677
3		 2.2751
3		 2.2417
2		 2.2716
3		 2.2098
3		 2.2098
3		 2.2113
3		 2.2100
3		 2.2099
3		 2.1964
3		     2.2405
2		 2.2272
2		   2.1574
1		      
M06-2X         2.2037
3		                            
PBEPBE 2.1137
2		 2.2905
3		 2.2613
2		 2.3251
2		 2.2307
3		 2.2307
3		 2.2326
3		 2.2315
3		 2.2315
3		 2.2163
3		 2.1547
1		   2.2318
3		 2.2179
3		 2.2466
2		     2.2470
2		 2.1560
1
PBEPBEultrafine         2.1683
1		                            
HSEh1PBE         2.2123
3		                            
Moller Plesset perturbation MP2FC 2.0905
2		 2.2746
3		 2.2082
3		 2.2709
3		 2.2090
3		 2.2090
3		 2.2124
3		 2.2123
3		 2.2123
3		 2.2059
3		   2.2310
3		 2.2188
3		 2.2341
2		 2.2047
3		 2.2394
3		 2.2140
3		 2.2004
2		 2.1544
1
MP2FU 2.0908
2		 2.2756
3		 2.2318
2		 2.2959
2		 2.2069
3		 2.2069
3		 2.2101
3		 2.2122
3		 2.2378
2		 2.2224
2		     2.2444
2		 2.2195
2		 2.1899
3		 2.1832
1		   2.2173
2		 2.1415
1
MP3         2.2100
3		                            
MP4   2.3127
2		     2.2217
3		     2.1741
1		 2.2481
2		         2.2169
3		          
B2PLYP         2.2175
3		   2.2202
3		                        
Configuration interaction CID   2.3118
2		 2.2314
2		 2.3100
2		 2.2087
3		     2.2104
3		                      
CISD   2.3343
2		 2.2361
2		 2.3395
2		 2.2131
3		     2.2396
2		                      
Quadratic configuration interaction QCISD   2.3289
3		 2.2454
2		 2.3635
2		 2.2242
3		 2.2480
2		 2.2263
3		 2.2248
3		 2.2249
3		 2.2367
2		     2.2331
3		 2.2138
3		         2.1649
1
QCISD(T)         2.2285
3		     2.1793
1		         2.2641
2		 2.2439
2		   2.2832
2		 2.2501
2		    
Coupled Cluster CCD   2.3134
2		 2.2339
2		 2.3117
2		 2.2132
3		 2.2362
2		 2.2397
2		 2.2149
3		 2.2383
2		 2.2303
2		     2.2229
3		 2.2318
2		   2.2671
2		 2.2371
2		    
CCSD         2.2193
3		     2.1720
1		                      
CCSD(T)   2.2548
1		     2.1747
1		 2.1747
1		 2.1768
1		 2.1757
1		 2.1757
1		   2.1675
1		   2.2357
3		 2.2177
3		   2.2547
3		 2.2234
3		   2.1674
1
CCSD(T)=FULL         2.2471
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 2.3778
2		 2.2101
3		 2.3786
3		 2.2088
3		 2.2630
3		 2.3415
3
density functional B1B95   2.1698
1		        
B3LYP 2.2976
3		 2.2319
3		 2.2974
3		 2.2322
3		 2.2722
3		 2.2864
3
Moller Plesset perturbation MP2FC 2.2872
3		 2.2287
3		 2.2740
3		 2.2162
3		 2.2722
3		 2.2698
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.