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

Geometry Comparison

C3H4N2 (1H-Imidazole)


distance is atom 3 (C) to atom 9 (N)

Experimental bond length is 1.377  Å

original data displayed. press to display differences
differences displayed. press to display original data

Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.403
PM6 1.336
composite G3 1.372
G3B3 1.381
CBS-Q 1.373

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 1.391 1.385 1.385 1.381 1.372 1.372 1.372 1.373 1.372 1.371 1.369 1.328 1.373 1.370 1.374 1.370
density functional LSDA 1.400 1.384 1.384 1.381 1.368 1.368 1.369 1.366 1.366 1.365     1.368 1.363 1.368  
BLYP 1.427 1.408 1.408 1.405 1.393 1.392 1.394 1.391 1.391 1.389     1.392 1.388 1.393  
B1B95 1.402 1.389 1.389 1.384 1.371 1.372 1.373 1.371 1.371 1.369     1.371 1.367 1.371  
B3LYP 1.412 1.395 1.395 1.392 1.381 1.380   1.380   1.378 1.376 1.326 1.380 1.376    
B3LYPultrafine         1.381   1.381                  
B3PW91   1.391 1.391 1.387 1.375 1.375 1.376 1.375   1.373     1.376 1.372 1.376  
mPW1PW91   1.389   1.385 1.373 1.373 1.374 1.372 1.372 1.371     1.373   1.374  
M06-2X         1.325                      
PBEPBE   1.400     1.384 1.384 1.385 1.382 1.383 1.381 1.380   1.384 1.380    
PBEPBEultrafine         1.384                      
Moller Plesset perturbation MP2FC   1.405 1.405 1.402 1.376 1.375 1.377 1.375 1.375 1.371   1.325 1.378      
MP2FU         1.374 1.374 1.376 1.373                
MP3         1.379                      
Configuration interaction CID         1.372                      
CISD         1.373                      
Quadratic configuration interaction QCISD   1.409     1.383       1.382              
Coupled Cluster CCD         1.378                      

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 1.393 1.382 1.392 1.381 1.387 1.387
density functional B1B95 1.398 1.383        
B3LYP 1.408 1.393 1.406 1.392 1.397 1.398
Moller Plesset perturbation MP2FC 1.422 1.389 1.415 1.386 1.412 1.412
Values that are outliers may reflect different atom numbering for different levels of theory.
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