return to home page Computational Chemistry Comparison and Benchmark DataBase Release 18 (October 2016) 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

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 ROHF/6-31G**
Calculated values were scaled by 0.8546.

Species Name mode Symmetry Experiment Theory difference ratio
C2H4+ Ethylene cation 4 Au 84 398 314 0.211
C2H Ethynyl radical 3 Π 372 638 266 0.583
CH2OH Hydroxymethyl radical 8 A 482 794 312 0.607
CH2OH Hydroxymethyl radical 9 A 234 348 114 0.672
ClCO carbonyl monochloride 3 A' 335 165 -169 2.022
C2H3+ vinyl cation 2 A1 2217 2751 534 0.806
CHCl2 dichloromethyl radical 4 A' 190 279 89 0.681
MgOH magnesium hydroxide 3 Π 188 124 -64 1.520
AlO Aluminum monoxide 1 Σ 979 685 -295 1.431
ClOO chloroperoxy radical 1 A' 1443 1024 -419 1.410
ClOO chloroperoxy radical 2 A' 414 685 271 0.604
ClOO chloroperoxy radical 3 A' 201 411 210 0.490
ZnCH3 Zinc monomethyl 6 E 315 551 236 0.572