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(T)/6-31+G**
Calculated values were scaled by 0.9596.

Species Name mode Symmetry Experiment Theory difference ratio
C2H2 Acetylene 4 Πg 612 383 -229 1.598
CH3 Methyl radical 2 A2" 606 466 -140 1.301
CH3CO Acetyl radical 4 A' 1420 3061 1641 0.464
CaOH Calcium monohydroxide 2 Σ 353 611 258 0.578
CaOH Calcium monohydroxide 3 Π 609 384 -225 1.584
H2OH2O water dimer 8 A' 103 161 58 0.638
H2OH2O water dimer 11 A" 108 159 51 0.680
H2OH2O water dimer 12 A" 88 135 47 0.653