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

Geometry Comparison

CH (Methylidyne)


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

Experimental bond length is 1.120  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical AM1 1.048
PM3 1.052
PM6 1.023
composite G2 1.071
G3 1.071
G3B3 1.095
G4 1.094
CBS-Q 1.074

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 1.077 1.072 1.072 1.071 1.071 1.072 1.072 1.072 1.073 1.072 1.105 1.072 1.082 1.071 1.070 1.081 1.071 1.070
ROHF   1.119 1.119   1.107 1.110 1.106 1.107         1.118 1.105        
density functional LSDA 1.104 1.105 1.105 1.104 1.101 1.102 1.104 1.103 1.102 1.102     1.113 1.102 1.101 1.114 1.102 1.101
BLYP 1.115 1.107 1.107 1.106 1.104 1.104 1.106 1.104 1.104 1.104     1.117 1.102   1.147    
B1B95 1.101 1.094 1.094 1.094 1.092 1.092 1.093 1.092 1.092 1.092     1.103 1.090 1.090 1.102 1.090 1.090
B3LYP 1.105 1.097 1.097 1.097 1.095 1.095 1.096 1.095 1.095 1.095 1.122 1.094 1.107 1.093 1.093 1.106 1.093 1.093
B3LYPultrafine         1.095                       1.092  
B3PW91 1.099 1.092 1.092 1.091 1.090 1.090 1.091 1.090 1.090 1.090     1.101 1.088   1.137    
mPW1PW91 1.097 1.090 1.090 1.089 1.088 1.088 1.089 1.088 1.088 1.088     1.099 1.087   1.135    
M06-2X         1.126                          
PBEPBE 1.107 1.102 1.102 1.101 1.099 1.099 1.100 1.099 1.099 1.099 1.136   1.110 1.098 1.098   1.136 1.098
PBEPBEultrafine         1.147                          
PBE1PBE         1.090                          
TPSSh         1.095   1.096             1.095        
Moller Plesset perturbation MP2 1.088 1.084 1.084 1.085 1.082 1.079 1.080 1.085 1.085 1.082   1.081 1.097 1.082 1.080 1.096 1.082 1.081
MP2=FULL 1.088 1.084 1.084 1.085 1.082 1.078 1.079 1.084 1.084 1.080     1.096 1.074 1.077 1.129   1.078
MP3         1.086   1.082                      
MP3=FULL         1.087   1.082                      
MP4   1.090     1.089     1.128 1.091                  
B2PLYP                           1.089        
Configuration interaction CID   1.091 1.091 1.093 1.088     1.091           1.118        
CISD   1.091 1.091 1.094 1.090     1.092           1.120        
Quadratic configuration interaction QCISD   1.092 1.092 1.095 1.090 1.084 1.086 1.093 1.092 1.089     1.104 1.088        
QCISD(T)         1.091 1.126 1.122 1.130         1.106 1.090   1.107 1.091  
Coupled Cluster CCD   1.091 1.091 1.094 1.089 1.083 1.085 1.091 1.091 1.087     1.103 1.086   1.104 1.086  
CCSD         1.090 1.125 1.121 1.129         1.142 1.121        
CCSD(T)   1.149     1.091 1.126 1.122 1.130 1.130   1.121   1.106 1.090   1.107 1.091  
CCSD(T)=FULL         1.091                       1.110  

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 1.084 1.081 1.080 1.076 1.076 1.076
density functional B1B95 1.155 1.140        
B3LYP 1.113 1.109 1.107 1.101 1.103 1.103
Moller Plesset perturbation MP2 1.102 1.097 1.095 1.088 1.093 1.093
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
Please use the error report form to report problems.