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

Geometry Comparison

CH3CH(NH2)COOH (Alanine)


distance is atom 3 (C) to atom 4 (C)

Experimental bond length is 1.544  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical AM1 1.526
PM3 1.531
composite G2 1.533
G3 1.533
G3B3 1.548
G4 1.544
CBS-Q 1.535

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   1.533 1.533 1.528 1.533 1.533 1.534 1.532 1.532 1.533 1.532 1.533 1.531 1.531 1.532  
density functional LSDA 1.623 1.553 1.553 1.537 1.534 1.534 1.533 1.532 1.532 1.532     1.533 1.528 1.528  
SVWN   1.516     1.534   1.521                  
BLYP   1.580 1.580 1.565 1.563 1.563 1.563 1.563 1.563 1.561     1.562 1.558 1.560  
B1B95   1.550 1.550 1.538 1.538 1.538 1.538 1.537 1.536 1.537     1.536 1.534 1.535  
B3LYP   1.559 1.559 1.547 1.548 1.547 1.548 1.547 1.547 1.546   1.544 1.546 1.543 1.545  
B3LYPultrafine         1.548                 1.542   1.543
B3PW91   1.557 1.557 1.544 1.544 1.544 1.544 1.542 1.542 1.543     1.542 1.539 1.541  
mPW1PW91   1.552 1.552 1.540 1.540 1.540 1.540 1.539 1.538 1.539     1.538 1.536 1.537  
M06-2X         1.537                      
PBEPBE   1.573 1.573 1.556 1.555 1.555 1.554 1.553 1.553 1.909     1.553 1.550 1.551  
PBEPBEultrafine         1.550                      
PBE1PBE         1.540                      
TPSSh         1.543   1.544             1.539    
Moller Plesset perturbation MP2   1.559 1.559 1.551 1.537 1.536 1.539 1.540 1.540 1.536   1.535 1.542 1.534 1.542  
MP2=FULL   1.559 1.559 1.551 1.535 1.534 1.536 1.538 1.538 1.529     1.541 1.526    
MP3         1.537   1.537                  
MP3=FULL         1.536   1.537                  
B2PLYP         1.541                 1.539    
B2PLYP=FULLultrafine         1.540                      
Configuration interaction CID   1.545 1.545 1.540 1.530     1.531 1.531              
CISD   1.546 1.546 1.540 1.530     1.531 1.531              
Quadratic configuration interaction QCISD   1.560     1.539               1.544      
Coupled Cluster CCD   1.556     1.537               1.543      

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 1.544   1.539   1.534 1.534
density functional B1B95 1.562 1.556        
B3LYP 1.571   1.562   1.556 1.556
Moller Plesset perturbation MP2 1.580   1.566   1.565 1.565
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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