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Comparison of experiment and theory for rII

Species with coordinate rII
Species Name
I2 Iodine diatomic
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
semi-empirical AM1 1 0.127
PM3 1 0.003

rms differences (calculated - experiment) in Å
Methods with standard basis sets
3-21G 3-21G* 6-31G* 6-311G* Def2TZVPP
hartree fock HF 1 0.199 1 0.031   1 0.037 1 0.032
density functional BLYP 1 0.273 1 0.084   1 0.109  
B1B95       1 0.028  
B3LYP 1 0.237 1 0.053   1 0.071 1 0.019
B3PW91 1 0.212 1 0.026   1 0.041  
mPW1PW91 1 0.203 1 0.018   1 0.032  
M06-2X   1 0.012      
PBEPBE 1 0.235 1 0.040   1 0.061 1 0.009
wB97X-D   1 0.007      
B97D3 1 0.229        
3-21G 3-21G* 6-31G* 6-311G* Def2TZVPP
Moller Plesset perturbation MP2 1 0.252 1 0.045 1 0.071 2 0.061 1 0.046
MP2=FULL 1 0.253 1 0.044   1 0.052  
MP3       1 0.065  
MP4 1 0.283     1 0.074  
Configuration interaction CID 1 0.272 1 0.049   1 0.047  
CISD 1 0.276 1 0.050   1 0.047  
3-21G 3-21G* 6-31G* 6-311G* Def2TZVPP
Quadratic configuration interaction QCISD 1 0.289 1 0.062   1 0.068  
QCISD(T)       1 0.078  
Coupled Cluster CCD 1 0.283 1 0.060   1 0.065  
CCSD(T)       1 0.078  
CCSD(T)=FULL       1 0.081  
3-21G 3-21G* 6-31G* 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         1 0.105   1 0.105   1 0.152 1 0.140
density functional B3LYP         1 0.158   1 0.158   1 0.197 1 0.187
Moller Plesset perturbation MP2         1 0.170   1 0.170   1 0.211 1 0.202
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.