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

Geometry Comparison

C6H8 (1,3-Cyclohexadiene)


distance is atom 2 (C) to atom 3 (H)

Experimental bond length is 1.466  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.451
PM6 1.464
composite G2 2.202
G3 2.202
G3B3 2.205
G4 1.469

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 1.489 1.476 1.476 1.471 2.202 1.475   1.476 1.475 1.475 1.473 1.471 1.477 1.473 1.476 1.472
density functional LSDA 1.470 1.454 1.454 1.452 1.449 1.449 1.449 1.446 1.446 1.446     1.450 1.444 1.450  
SVWN   1.458     1.449   1.455                  
BLYP 1.497 1.479 1.479 1.476 1.472 1.472 1.473 1.472 1.472 1.470     1.474 1.468 1.474  
B1B95 1.481 1.467 1.467 1.463 1.461 1.461 1.461 1.459 1.459 1.459     1.461 1.456 1.461 1.456
B3LYP 1.490 1.472 1.472 1.469 1.467 1.467 1.467 1.466   1.465 1.462 1.464 1.468 1.462    
B3LYPultrafine         1.467                 2.199   1.467
B3PW91   1.469 1.469 1.465 1.463 1.463 1.463 1.462   1.461     1.464 1.459 1.464  
mPW1PW91   1.467 1.467 1.464 1.462 1.462 1.462 1.461 1.461 1.460     1.463 1.458 2.207  
M06-2X         1.470                      
PBEPBE   1.472     1.466 1.466 1.466 1.464 1.464 1.464 1.461   1.467 1.461    
PBEPBEultrafine         2.215                      
PBE1PBE         1.462                      
HSEh1PBE         1.464                      
TPSSh         1.471   1.472             1.467    
Moller Plesset perturbation MP2   1.484 1.484 1.483 2.207 1.463 2.205 1.466 1.466     1.464 1.470 1.465    
MP2=FULL   1.484 1.484 1.482 1.462   1.462 1.464         1.469 1.458    
MP3         1.472   1.475                  
MP3=FULL         1.474   1.474                  
MP4       1.483                        
B2PLYP         1.468                 1.462    
B2PLYP=FULLultrafine         2.205                      
Configuration interaction CID         1.469                      
CISD         1.469                      
Quadratic configuration interaction QCISD   1.493     1.474 1.474                    

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 1.490 1.490 1.485 1.485 1.478 1.478
density functional B1B95 1.484 1.480        
B3LYP 1.490 1.485 1.484 1.479 1.476 1.476
Moller Plesset perturbation MP2 1.509 1.484 1.500 1.475 1.496 1.496
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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