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III.G.1.a.

Comparison of levels of theory for Cl-Cl


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 2.0062
2
PM3 2.1216
3
PM6 2.0821
3
composite G2 2.1783
3
G3 2.1783
3
G3B3 2.2442
3
CBS-Q 2.1783
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(D+d)Z cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ Sadlej_pVTZ
hartree fock HF 2.2039
3		 2.3262
3		 2.1762
3		 2.3083
3		 2.1783
3		 2.1783
3		 2.1813
3		 2.1932
3		 2.1932
3		 2.1616
3		 1.9742
1		 2.1870
3		 2.1844
3		 2.1654
3		 1.9785
1		 2.1876
3		 2.1647
3		 1.9782
1		 1.9904
1		 2.1581
3		     2.0101
1
ROHF         2.2644
2		                                    
density functional LSDA 2.2566
3		 2.2556
3		 2.1913
3		 2.3345
3		 2.1943
3		 2.1943
3		 2.1939
3		 2.2087
3		 2.2087
3		 2.1603
3		     2.1937
3		 2.1673
3		   2.1849
3		 2.2468
2		   1.9928
1		        
SVWN   2.3478
3		     2.3289
2		   2.1939
3		                                
BLYP 2.3260
3		 2.4343
3		 2.2907
3		 2.4332
3		 2.2982
3		 2.2982
3		 2.2964
3		 2.3106
3		 2.3109
3		 2.2670
3		     2.2977
3		 2.2740
3		   2.0787
1		     2.0265
1		        
B1B95 2.2627
3		 2.2692
3		 2.2046
3		 2.3491
3		 2.2069
3		 2.2082
3		 2.3558
2		 2.2232
3		 2.2232
3		 2.1811
3		     2.2100
3		 2.1854
3		   2.2046
3		 2.6537
1		   1.9940
1		 1.9837
1		      
B3LYP 2.2826
3		 2.3878
3		 2.2393
3		 2.3786
3		 2.2442
3		 2.2442
3		 2.2447
3		 2.2585
3		 2.3588
2		 2.2171
3		 2.0106
1		 2.2492
3		 2.2457
3		 2.2230
3		 2.0175
1		 2.2408
3		 2.2189
3		 2.0171
1		 2.0118
1		 2.2125
3		     2.0501
1
B3LYPultrafine         2.2440
3		                                    
B3PW91 2.3508
2		 2.3670
3		 2.2134
3		 2.3550
3		 2.2173
3		 2.2173
3		 2.2172
3		 2.2298
3		 2.3285
2		 2.1888
3		     2.2186
3		 2.1939
3		   2.0250
1		     1.9998
1		        
mPW1PW91 2.3368
2		 2.3552
3		 2.2944
2		 2.3417
3		 2.2044
3		 2.2044
3		 2.2048
3		 2.2173
3		 2.2175
3		 2.1768
3		     2.2061
3		 2.1819
3		   2.0176
1		     1.9957
1		        
M06-2X         2.1897
3		                           1.9988
1		        
PBEPBE 2.3846
2		 2.3965
3		 2.3429
2		 2.4803
2		 2.2493
3		 2.2493
3		 2.2491
3		 2.2627
3		 2.2627
3		 2.2161
3		 2.0059
1		   2.2482
3		 2.2219
3		     2.0201
1		   2.0087
1		 2.0070
1		     2.0225
1
PBEPBEultrafine         2.0415
1		                                    
HSEh1PBE         2.2049
3		                           1.9955
1		        
Moller Plesset perturbation MP2FC 2.5361
1		 2.4098
3		 2.1957
3		 2.3952
3		 2.1988
3		 2.1988
3		 2.2005
3		 2.2099
3		 2.2101
3		 2.2419
2		   2.1993
3		 2.2017
3		 2.1613
3		 1.9853
1		 2.2078
3		 2.1598
3		 1.9852
1		 2.0026
1		 2.1527
3		 2.0244
1		 1.9872
1		 2.0407
1
MP2FU 2.5361
1		 2.4102
3		 2.2839
2		 2.4785
2		 2.1983
3		 2.1983
3		 2.2000
3		 2.2096
3		 2.3009
2		 2.2374
2		     2.2012
3		 2.1567
3		 1.9819
1		 2.0391
1		 1.9920
1		   2.0016
1		 2.1463
3		 2.0228
1		 1.9835
1		  
MP3         2.2045
3		                                    
MP4   2.4790
2		     2.2135
3		     2.0490
1		 2.3191
2		         2.1797
3		         2.0316
1		        
B2PLYP         2.2204
3		   2.2226
3		                       2.0072
1		        
Configuration interaction CID   2.4525
2		 2.2765
2		 2.4474
2		 2.1941
3		     2.2051
3		                              
CISD   2.4574
2		 2.2788
2		 2.4528
2		 2.1964
3		     2.2986
2		                              
Quadratic configuration interaction QCISD   2.4080
3		 2.2876
2		 2.4638
2		 2.2068
3		 2.2960
2		 2.2117
3		 2.2205
3		 2.2206
3		 2.2544
2		     2.2107
3		 2.1747
3		         2.0106
1		 2.0003
1		      
QCISD(T)         2.2144
3		     2.0523
1		         2.2995
2		 2.2619
2		   2.3115
2		 2.2620
2		            
Coupled Cluster CCD   2.4616
2		 2.2834
2		 2.4563
2		 2.2024
3		 2.2912
2		 2.2951
2		 2.2149
3		 2.3040
2		 2.2511
2		     2.2070
3		 2.2532
2		   2.2990
2		 2.2519
2		   2.0091
1		 1.9980
1		      
CCSD         2.2062
3		     2.0403
1		                              
CCSD(T)   2.2959
1		     2.0379
1		 2.0379
1		 2.0425
1		 2.0519
1		 2.0519
1		   2.0057
1		   2.2176
3		 2.1803
3		   2.2281
3		 2.1810
3		   2.0351
1		 2.0079
1		 2.0483
1		 2.0075
1		  
CCSD(T)=FULL         2.2138
3		               2.0541
1		 2.0132
1		   2.0625
1		 2.0123
1		   2.0338
1		 2.0019
1		 2.0466
1		 2.0042
1		  
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 2.3024
3		 2.1835
3		 2.3023
3		 2.1821
3		 2.3121
3		 2.3218
3
density functional B1B95 2.1847
1		 2.0301
1		        
B3LYP 2.3794
3		 2.2471
3		 2.3788
3		 2.2454
3		 2.3915
3		 2.3942
3
Moller Plesset perturbation MP2FC 2.3867
3		 2.1967
3		 2.3872
3		 2.1966
3		 2.3947
3		 2.4022
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.