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

Geometry Comparison

Br2 (Bromine diatomic)


distance is atom 1 (Br) to atom 2 (Br)

Experimental bond length is 2.281  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 2.443
PM6 2.328
composite G2 2.286
G3B3 2.333
G4 2.321

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 cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
hartree fock HF   2.443 2.270 2.426 2.286 2.286 2.286 2.289   2.256 2.272 2.298 2.297 2.276 2.273 2.298 2.276 2.273
density functional LSDA 2.319 2.438 2.253 2.428 2.281 2.281 2.282 2.293 2.293 2.252     2.292 2.272   2.293    
SVWN   2.439     2.281   2.283                      
BLYP   2.503 2.320 2.497 2.352 2.352 2.355 2.369   2.325     2.368 2.348        
B1B95 2.317 2.450 2.267 2.438 2.286 2.289 2.290 2.300 2.300 2.261     2.302 2.279   2.299    
B3LYP 2.338 2.474 2.294 2.465 2.322 2.322 2.324 2.334   2.293   2.338 2.335 2.315 2.313 2.335 2.316 2.313
B3LYPultrafine                                 2.319  
B3PW91   2.459 2.275 2.446 2.298 2.298 2.299 2.308   2.270     2.311 2.290        
mPW1PW91 2.218 2.452 2.269 2.438 2.291 2.291 2.291 2.300   2.263     2.302 2.283        
M06-2X         2.287                          
PBEPBE   2.477 2.289 2.467 2.315 2.315 2.317 2.330   2.288     2.330 2.310   2.330 2.311  
PBEPBEultrafine         2.315                          
PBE1PBE         2.288                          
HSEh1PBE         2.293                          
TPSSh         2.312   2.312             2.300        
Moller Plesset perturbation MP2   2.489 2.284 2.481 2.313 2.313 2.314 2.308   2.267   2.312 2.315 2.277 2.261 2.324 2.279 2.261
MP2=FULL   2.489 2.283 2.482 2.308 2.308 2.309 2.304   2.257     2.314 2.272 2.257 2.324    
MP3         2.326   2.341                      
MP3=FULL         2.336   2.337                      
MP4   2.514     2.331                 2.299        
B2PLYP         2.316                 2.306        
Configuration interaction CID   2.504 2.287 2.497 2.314     2.309                    
CISD   2.507 2.288 2.501 2.315     2.311                    
Quadratic configuration interaction QCISD   2.518 2.299 2.513 2.327 2.327 2.329 2.324   2.283     2.333 2.293        
QCISD(T)         2.334                          
Coupled Cluster CCD   2.513 2.297 2.507 2.325 2.325 2.327 2.321   2.280     2.330          
CCSD         2.327                          
CCSD(T)         2.334               2.341 2.302   2.349 2.303  

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 2.392   2.392   2.462 2.399
density functional B1B95 2.428          
B3LYP 2.448   2.448   2.510 2.451
Moller Plesset perturbation MP2 2.464   2.464   2.519 2.464
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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