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/6-311G**
Calculated values were scaled by 0.9126.

Species Name mode Symmetry Experiment Theory difference ratio
C2H4+ Ethylene cation 4 Au 84 420 336 0.200
C2H Ethynyl radical 3 Π 372 545 173 0.682
CH3 Methyl radical 2 A2" 606 343 -264 1.770
CH2OH Hydroxymethyl radical 8 A 482 822 340 0.586
CH2OH Hydroxymethyl radical 9 A 234 379 145 0.617
C2H3+ vinyl cation 2 A1 2217 2910 693 0.762
CHCl2 dichloromethyl radical 4 A' 190 297 107 0.641
O2+ diatomic oxygen cation 1 Σg 1906 2315 409 0.823
ZnCl Zinc monochloride 1 Σ 391 284 -107 1.375
S3- Sulfur trimer anion 3 B2 594 410 -184 1.450
ZnCH3 Zinc monomethyl 6 E 315 584 269 0.540
HSO3 HOSO2 4 A 1097 829 -268 1.323