return to home page Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
You are here: Calculated > Vibrations > Bad Calculations > Bad vib. Calc. vs exp. OR Resources > Bad Calculations > Vibrations > Bad vib. Calc. vs exp.

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 QCISD(TQ)/3-21G
Calculated values were scaled by 1.

Species Name mode int rot Symmetry Experiment Theory difference ratio
C2H2 Acetylene 4 Πg 612 480 -132 1.275
CO2 Carbon dioxide 3 Πu 667 551 -116 1.211
SO2 Sulfur dioxide 1 A1 1151 870 -281 1.323
SO2 Sulfur dioxide 2 A1 518 409 -109 1.266
SO2 Sulfur dioxide 3 B2 1362 1027 -335 1.327
O2 Oxygen diatomic 1 Σg 1556 1268 -288 1.227
Cl2 Chlorine diatomic 1 Σg 554 394 -160 1.405
NO Nitric oxide 1 Σ 1876 1352 -524 1.388