return to home page Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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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/6-311G*
Calculated values were scaled by 1.

Species Name mode int rot Symmetry Experiment Theory difference ratio
C2H2 Acetylene 4 Πg 612 355 -257 1.725
CH2I2 Diiodomethane 3 A1 704 481 -223 1.464
CH2I2 Diiodomethane 4 A1 285 119 -166 2.403
CH2I2 Diiodomethane 7 B1 896 738 -158 1.214
CH2I2 Diiodomethane 9 B2 738 578 -160 1.277
N2O Nitrous oxide 1 Σ 2224 2644 420 0.841
N2O Nitrous oxide 3 Π 589 465 -124 1.267