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 CCSD(T)=FULL/3-21G
Calculated values were scaled by 1.

Species Name mode int rot Symmetry Experiment Theory difference ratio
C2H2 Acetylene 4 Πg 612 483 -129 1.267
CO2 Carbon dioxide 3 Πu 667 548 -119 1.217
SO2 Sulfur dioxide 1 A1 1151 818 -333 1.407
SO2 Sulfur dioxide 2 A1 518 401 -117 1.291
SO2 Sulfur dioxide 3 B2 1362 937 -425 1.454
O2 Oxygen diatomic 1 Σg 1556 1281 -276 1.215
Cl2 Chlorine diatomic 1 Σg 554 398 -156 1.392
IBr Iodine monobromide 1 Σ 267 212 -55 1.260
ICl Iodine monochloride 1 Σ 381 298 -83 1.279
NO Nitric oxide 1 Σ 1876 1430 -446 1.312