return to home page Computational Chemistry Comparison and Benchmark DataBase Release 19 (April 2018) Standard Reference Database 101 National Institute of Standards and Technology
You are here: Home > Geometry > Experimental > Same bond/angle many molecules OR Comparisons > Geometry > Bonds, angles > Same bond/angle many molecules

Comparison of experiment and theory for rCI

Species with coordinate rCI
Species Name
CH3I methyl iodide
ICN Cyanogen iodide
CF3I trifluoroiodomethane
The small prefix is the number of bonds with completed calculations.
Click on an entry for a histogram of the difference distribution.
rms differences (calculated - experiment) in Å
Methods with predefined basis sets

rms differences (calculated - experiment) in Å
Methods with standard basis sets
3-21G 3-21G* 6-31G* 6-311G* 6-311G** Def2TZVPP
hartree fock HF 1 0.058 1 0.043   2 0.017   2 0.010
density functional LSDA       1 0.014    
BLYP 1 0.105 1 0.084   2 0.074    
B1B95   1 0.032   2 0.013    
B3LYP 1 0.077 1 0.058   2 0.041   2 0.032
B3PW91 1 0.058 1 0.040   2 0.025    
mPW1PW91 1 0.051 1 0.034   2 0.018    
M06-2X   3 0.025   1 0.013    
PBEPBE 1 0.072 1 0.053   2 0.045   2 0.037
PBE1PBE       1 0.020    
wB97X-D   2 0.039        
B97D3 2 0.109          
3-21G 3-21G* 6-31G* 6-311G* 6-311G** Def2TZVPP
Moller Plesset perturbation MP2 1 0.068 1 0.063 2 0.037 3 0.017   2 0.025
MP2=FULL 1 0.067 1 0.062   2 0.019    
ROMP2       1 0.020    
Configuration interaction CID 1 0.070 1 0.059   2 0.010    
CISD 1 0.074 1 0.061   2 0.012    
3-21G 3-21G* 6-31G* 6-311G* 6-311G** Def2TZVPP
Quadratic configuration interaction QCISD 1 0.083 1 0.071   2 0.025 1 0.022  
QCISD(T) 1 0.086 1 0.077   1 0.033    
Coupled Cluster CCD 1 0.076 1 0.068   2 0.021    
CCSD(T) 1 0.086 1 0.077   1 0.032 1 0.026  
3-21G 3-21G* 6-31G* 6-311G* 6-311G** Def2TZVPP

rms differences (calculated - experiment) in Å
Methods with effective core potentials (select basis sets)
daug-cc-pVDZ daug-cc-pVTZ daug-cc-pVQZ Sadlej_pVTZ CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF         2 0.032   2 0.028   2 0.032 2 0.036
density functional B1B95         1 0.041   1 0.036   1 0.041 1 0.047
B3LYP         2 0.051   2 0.064   2 0.045 2 0.054
Moller Plesset perturbation MP2         2 0.046   2 0.042   2 0.045 2 0.051
For descriptions of the methods (AM1, HF, MP2, ...) and basis sets (3-21G, 3-21G*, 6-31G, ...) see the glossary in section I.C. Predefined means the basis set used is determined by the method.