return to home page Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) 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

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/STO-3G
Calculated values were scaled by 1.

Species Name mode int rot Symmetry Experiment Theory difference ratio
H2CO Formaldehyde 1 A1 2782 3197 415 0.870
H2CO Formaldehyde 5 B2 2843 3318 475 0.857
CH4 Methane 3 T2 3019 3480 461 0.867
C2H6 Ethane 7 Eg 2969 3434 465 0.865
C2H6 Ethane 10 Eu 2985 3446 461 0.866
C2H4 Ethylene 8 B2u 3105 3512 408 0.884
C2H4 Ethylene 10 B3g 3086 3500 414 0.882
C3H6 Cyclopropane 6 A2" 3103 3511 408 0.884
C3H6 Cyclopropane 12 E" 3082 3505 423 0.879
CH2CHCH3 Propene 1 A' 3090 3505 415 0.882
CH2CHCH3 Propene 2 A' 3013 3441 428 0.876
CH2CHCH3 Propene 3 A' 2991 3407 416 0.878
CH2CHCH3 Propene 4 A' 2954 3364 410 0.878
CH2CHCH3 Propene 15 A" 2954 3418 464 0.864
CO2 Carbon dioxide 3 Πu 667 469 -198 1.421
C3H5 Allyl radical 1 A1 3114 3517 403 0.885
C3H5 Allyl radical 13 B2 3105 3516 411 0.883
SO2 Sulfur dioxide 2 A1 518 409 -109 1.265
SO2 Sulfur dioxide 3 B2 1362 1119 -243 1.217
NH3 Ammonia 2 torsion A1 950 1492 542 0.637
H2O Water 1 A1 3657 2946 -711 1.241
H2O Water 3 B2 3756 3263 -493 1.151
NI3 Nitrogen triiodide 1 A1 279 418 139 0.667
NI3 Nitrogen triiodide 3 E 354 571 217 0.620
Na2 Sodium diatomic 1 Σg 158 483 326 0.326