return to home page Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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Bad vibrational frequency predictions

19 02 11 15 45

Calculated frequencies that differ from experiment by more than 400 cm-1 or have a ratio with experiment outside of 0.7 to 1.2 are listed

Calculated vibrational frequencies ("theory" in table) are calculated at MP4/3-21G*
Calculated values were scaled by 0.9438.

Species Name mode int rot Symmetry Experiment Theory difference ratio
C2H2 Acetylene 4 Πg 612 450 -162 1.361
CO2 Carbon dioxide 3 Πu 667 503 -164 1.326
CO Carbon monoxide 1 Σ 2143 1611 -532 1.330
SO2 Sulfur dioxide 1 A1 1151 825 -326 1.395
SO2 Sulfur dioxide 3 B2 1362 1067 -294 1.276
N2 Nitrogen diatomic 1 Σg 2330 1817 -513 1.282
O2 Oxygen diatomic 1 Σg 1556 1060 -496 1.468
NO Nitric oxide 1 Σ 1876 3541 1665 0.530
Na2 Sodium diatomic 1 Σg 158 121 -37 1.306