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

Geometry Comparison

C5H8 (Bicyclo[2.1.0]pentane)


distance is atom 1 (C) to atom 5 (C)

Experimental bond length is 1.536  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.504
PM6 1.522
composite G2 1.493
G3 1.493
G3B3 1.504
G4 1.502
CBS-Q 2.170

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 1.503 1.511 1.511 1.505 1.493 1.493 1.495 1.495 1.495 1.493 1.492 1.492 1.496 1.491 1.498 1.491
density functional LSDA 1.517 1.509 1.509 1.504 1.491 1.491 1.492 1.488 1.489 1.490     1.494 1.485 1.494  
SVWN   1.509     1.491   1.493                  
BLYP 1.544 1.536 1.536 1.530 1.516 1.516 1.518 1.514 1.515 1.515     1.518 1.511 1.519  
B1B95 1.517 1.515 1.515 1.508 1.494 1.495 1.496 1.494 1.494 1.494     1.496 1.490 1.496  
B3LYP 1.529 1.522 1.522 1.517 1.504 1.504 1.506 1.503   1.503 1.499 1.501 1.506 1.499 1.507  
B3LYPultrafine         1.504   1.506             1.499   1.498
B3PW91   1.519 1.519 1.512 1.500 1.500 1.501 1.498   1.499     1.502 1.495 1.502  
mPW1PW91   1.516 1.516 1.510 1.497 1.497 1.498 1.496 1.497 1.496     1.499 1.493 1.500  
M06-2X         1.497                      
PBEPBE   1.528     1.508 1.508 1.510 1.506 1.507 1.507 1.503   1.509 1.504    
PBEPBEultrafine         1.508                      
PBE1PBE         1.497                      
HSEh1PBE         1.497                      
TPSSh         1.502   1.503             1.498    
Moller Plesset perturbation MP2   1.530 1.530 1.526 1.498 1.498 1.501 1.504 1.504 1.500   1.499 1.510 1.497 1.513  
MP2=FULL   1.529 1.529 1.526 1.497 1.496 1.499 1.502         1.508 1.492    
MP3         1.502   1.500                  
MP3=FULL         1.499   1.500                  
B2PLYP         1.502                 1.498    
B2PLYP=FULLultrafine         1.501                      
Configuration interaction CID   1.522     1.494 1.493 1.494                  
CISD   1.523     1.494 1.493                    
Quadratic configuration interaction QCISD   1.535 1.535 1.530 1.503 1.502 1.504 1.507         1.513      
Coupled Cluster CCD   1.533 1.533 1.528 1.502 1.500 1.503 1.506         1.512      

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 1.525 1.510 1.521 1.504 1.517 1.517
density functional B1B95 1.532 1.516        
B3LYP 1.542 1.525 1.536 1.518 1.530 1.530
Moller Plesset perturbation MP2 1.560 1.525 1.550 1.515 1.550 1.550
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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