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

Geometry Comparison

NH (Imidogen)


distance is atom 1 (N) to atom 2 (H)

Experimental bond length is 1.034  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical AM1 0.987
PM3 0.974
PM6 0.998
composite G2 1.020
G3 1.020
G3B3 1.046
G4 1.043
CBS-Q 1.018

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 1.079 1.041 1.041 1.028 1.020 1.020 1.019 1.017 1.019 1.018 1.020 1.018 1.027 1.017 1.016 1.024 1.017 1.016
ROHF   1.044 1.044   1.021 1.022 1.021 1.018         1.029 1.018        
density functional LSDA 1.119 1.087 1.087 1.072 1.058 1.056 1.055 1.055 1.054 1.053     1.064 1.052   1.059 1.052  
SVWN   1.087     1.060   1.055                      
BLYP 1.131 1.089 1.089 1.073 1.059 1.057 1.055 1.055 1.054 1.054     1.066 1.050   1.059    
B1B95 1.110 1.069 1.069 1.055 1.042 1.041 1.040 1.039 1.039 1.039     1.049 1.037 1.035 1.043 1.036 1.035
B3LYP 1.115 1.073 1.073 1.059 1.046 1.045 1.043 1.042 1.042 1.042 1.040 1.041 1.053 1.039 1.038 1.046 1.039 1.038
B3LYPultrafine         1.046                       1.039  
B3PW91 1.112 1.071 1.071 1.057 1.044 1.043 1.042 1.041 1.041 1.041     1.051 1.039   1.047    
mPW1PW91 1.108 1.067 1.067 1.053 1.041 1.040 1.039 1.038 1.039 1.038     1.048 1.037   1.044    
M06-2X         1.041                          
PBEPBE 1.125 1.087 1.087 1.071 1.057 1.055 1.054 1.054 1.053 1.053 1.050   1.064 1.051 1.050 1.057 1.050 1.050
PBEPBEultrafine         1.057                          
PBE1PBE         1.043                          
HSEh1PBE         1.043                          
TPSSh         1.047   1.045             1.042        
Moller Plesset perturbation MP2 1.099 1.063 1.063 1.052 1.038 1.033 1.033 1.032 1.033 1.032   1.032 1.044 1.030 1.029 1.042 1.031 1.030
MP2=FULL 1.099 1.063 1.063 1.052 1.037 1.032 1.033 1.032 1.033 1.031     1.043 1.028 1.027 1.041 1.026  
MP3         1.042   1.036                      
MP3=FULL         1.042   1.035                      
MP4   1.072     1.045     1.040 1.039         1.037        
B2PLYP         1.041                 1.034        
Configuration interaction CID   1.067 1.067 1.055 1.040     1.034           1.033        
CISD   1.068 1.068 1.056 1.041     1.035           1.035        
Quadratic configuration interaction QCISD   1.073 1.073 1.060 1.045 1.038 1.038 1.039 1.039 1.036     1.050 1.034        
QCISD(T)         1.046 1.044 1.043 1.043         1.052 1.036   1.048 1.037  
Coupled Cluster CCD   1.071 1.071 1.058 1.044 1.037 1.036 1.037 1.037 1.035     1.049 1.033   1.045 1.033  
CCSD         1.044 1.042 1.041 1.041         1.054 1.037        
CCSD(T)   1.076     1.046 1.044 1.043 1.043 1.044   1.039   1.052 1.036 1.034 1.048 1.037 1.035
CCSD(T)=FULL         1.119                   1.032     1.033

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 1.035 1.025 1.036 1.023 1.034 1.034
density functional B1B95 1.064 1.050        
B3LYP 1.067 1.053 1.066 1.050 1.066 1.066
Moller Plesset perturbation MP2 1.061 1.045 1.060 1.041 1.061 1.061
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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