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Comparison of experiment and theory for rHI

Species with coordinate rHI
Species Name
HI Hydrogen iodide
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**
hartree fock HF 1 0.029 1 0.022   1 0.015 1 0.000
density functional BLYP 1 0.068 1 0.051   1 0.045 1 0.030
B1B95 1 0.044 1 0.030   1 0.023 1 0.009
B3LYP 1 0.052 1 0.038   1 0.032 1 0.017
B3PW91 1 0.048 1 0.033   1 0.028 1 0.014
mPW1PW91 1 0.045 1 0.031   1 0.025 1 0.011
PBEPBE 1 0.062 1 0.045   1 0.040 1 0.025
wB97X-D   1 0.028      
B97D3 1 0.061        
3-21G 3-21G* 6-31G* 6-311G* 6-311G**
Moller Plesset perturbation MP2 1 0.048 1 0.036 1 0.033 2 0.033 1 0.003
MP2=FULL 1 0.048 1 0.036   1 0.029 1 0.002
Configuration interaction CID 1 0.061 1 0.042   1 0.031 1 0.003
CISD 1 0.063 1 0.043   1 0.032 1 0.002
3-21G 3-21G* 6-31G* 6-311G* 6-311G**
Quadratic configuration interaction QCISD 1 0.065 1 0.047   1 0.039 1 0.003
QCISD(T) 1 0.065 1 0.049   1 0.042 1 0.004
Coupled Cluster CCD 1 0.063 1 0.046   1 0.038 1 0.002
CCSD(T) 1 0.065 1 0.049   1 0.042 1 0.004
3-21G 3-21G* 6-31G* 6-311G* 6-311G**

rms differences (calculated - experiment) in Å
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 1 0.007   1 0.004   1 0.006 1 0.008
density functional B1B95 1 0.032   1 0.030   1 0.029 1 0.032
B3LYP 1 0.031   1 0.029   1 0.027 1 0.030
Moller Plesset perturbation MP2 1 0.028   1 0.025   1 0.024 1 0.028
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.