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 MP4/CEP-31G
Calculated values were scaled by 0.9438.

Species Name mode int rot Symmetry Experiment Theory difference ratio
C2H4 Ethylene 7 B2g 940 690 -250 1.363
CO2 Carbon dioxide 1 Σg 1333 1010 -323 1.320
CO2 Carbon dioxide 3 Πu 667 500 -167 1.333
CO Carbon monoxide 1 Σ 2143 1503 -640 1.426
SO2 Sulfur dioxide 1 A1 1151 844 -307 1.364
SO2 Sulfur dioxide 2 A1 518 344 -174 1.504
NH3 Ammonia 2 torsion A1 950 731 -219 1.299
N2 Nitrogen diatomic 1 Σg 2330 1793 -537 1.299
F2 Fluorine diatomic 1 Σg 894 693 -201 1.290
O2 Oxygen diatomic 1 Σg 1556 1153 -404 1.350
Cl2 Chlorine diatomic 1 Σg 554 380 -174 1.457
IBr Iodine monobromide 1 Σ 267 197 -70 1.358
ICl Iodine monochloride 1 Σ 381 283 -99 1.348
NO Nitric oxide 1 Σ 1876 2951 1075 0.636
BF Boron monofluoride 1 Σ 1379 1023 -356 1.348
Na2 Sodium diatomic 1 Σg 158 122 -35 1.290