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IV.D.1. (XII.C.1.)

Geometry Comparison

C6H8 (1,3-Cyclohexadiene)


distance is atom 1 (H) to atom 7 (H)

Experimental bond length is 1.090  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.095
PM6 1.091
composite G2 2.427
G3 2.427
G3B3 2.456
G4 1.086

Calculated bond length in 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 aug-cc-pVDZ aug-cc-pVTZ
hartree fock HF 1.083 1.073 1.073 1.074 2.427 1.077   1.077 1.077 1.077 1.075 1.075 1.084 1.075 1.082 1.074
density functional LSDA 1.100 1.095 1.095 1.096 1.097 1.096 1.097 1.095 1.094 1.095     1.102 1.093 1.101  
SVWN   1.097     1.097   1.098                  
BLYP 1.107 1.093 1.093 1.095 1.095 1.094 1.095 1.093 1.092 1.093     1.101 1.089 1.099  
B1B95 1.097 1.084 1.084 1.086 1.086 1.086 1.086 1.085 1.084 1.085     1.092 1.082 1.090 1.082
B3LYP 1.099 1.086 1.086 1.087 1.088 1.087 1.087 1.086   1.086 1.083 1.085 1.094 1.083    
B3LYPultrafine         1.088                 2.447   1.083
B3PW91   1.087 1.087 1.087 1.088 1.088 1.088 1.087   1.087     1.094 1.084 1.092  
mPW1PW91   1.085 1.085 1.086 1.086 1.086 1.086 1.085 1.085 1.085     1.092 1.083 2.452  
M06-2X         1.087                      
PBEPBE   1.095     1.096 1.095 1.096 1.095 1.094 1.094 1.092   1.101 1.092    
PBEPBEultrafine         2.483                      
PBE1PBE         1.088                      
HSEh1PBE         1.088                      
TPSSh         1.088   1.088             1.085    
Moller Plesset perturbation MP2   1.087 1.087 1.091 2.461 1.083 2.466 1.088 1.087     1.085 1.096 1.083    
MP2=FULL   1.087 1.087 1.091 1.088   1.083 1.087         1.095 1.078    
MP3         1.087   1.082                  
MP3=FULL         1.088   1.082                  
MP4       1.091                        
B2PLYP         1.087                 1.082    
B2PLYP=FULLultrafine         2.463                      
Configuration interaction CID         1.081                      
CISD         1.081                      
Quadratic configuration interaction QCISD   1.091     1.090 1.084                    

Calculated bond length in Å
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 1.079 1.082 1.077 1.079 1.074 1.074
density functional B1B95 1.093 1.094        
B3LYP 1.095 1.095 1.090 1.091 1.089 1.089
Moller Plesset perturbation MP2 1.103 1.097 1.096 1.090 1.096 1.096
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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