return to home page Computational Chemistry Comparison and Benchmark DataBase Release 18 (October 2016) Standard Reference Database 101 National Institute of Standards and Technology
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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 CCSD/6-311G*
Calculated values were scaled by 0.9535.

Species Name mode Symmetry Experiment Theory difference ratio
CH3OH Methyl alcohol 12 A" 200 345 145 0.580
C2H2 Acetylene 4 Πg 612 410 -202 1.493
LiOH lithium hydroxide 3 Π 257 389 132 0.659
NaOH sodium hydroxide 3 Π 300 215 -85 1.394
CH3 Methyl radical 2 A2" 606 428 -179 1.417
CH2OH Hydroxymethyl radical 9 A 234 447 213 0.524
CH3CO Acetyl radical 4 A' 1420 2995 1575 0.474
CaOH Calcium monohydroxide 2 Σ 353 626 273 0.563
CaOH Calcium monohydroxide 3 Π 609 366 -243 1.663
Mg2 Magnesium diatomic 1 Σg 51 15 -36 3.492
Al2 Aluminum diatomic 1 Σg 286 444 158 0.644