return to home page Computational Chemistry Comparison and Benchmark DataBase Release 19 (April 2018) 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

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)/6-31G**
Calculated values were scaled by 0.9485.

Species Name mode Symmetry Experiment Theory difference ratio
C2H2 Acetylene 4 Πg 612 371 -241 1.652
CH3OH Methyl alcohol 12 A" 200 325 125 0.616
CH3CCH propyne 10 E 328 246 -82 1.332
C10H8 naphthalene 27 B2g 770 410 -360 1.880
C10H8 naphthalene 28 B2g 461 234 -227 1.968
F2CCCF2 tetrafluoroallene 5 B2 2052 687 -1365 2.989
F2CCCF2 tetrafluoroallene 6 B2 1030 537 -493 1.918
F2CCCF2 tetrafluoroallene 7 B2 581 366 -215 1.587
F2CCCF2 tetrafluoroallene 11 E 90 64 -26 1.413
C3H6O Oxetane 18 B1 90 -74 -164 -1.216
H2CS- thioformaldehyde anion 4 B1 450 -167 -617 -2.694
C6H6 Benzvalene 10 A1 996 743 -253 1.341
NaOH sodium hydroxide 3 Π 300 120 -180 2.500
C2H Ethynyl radical 3 Π 372 277 -95 1.343
CH3 Methyl radical 2 A2" 606 398 -208 1.522
CH2OH Hydroxymethyl radical 8 A 482 710 228 0.679
CH2OH Hydroxymethyl radical 9 A 234 425 191 0.550
CHCl2 dichloromethyl radical 4 A' 190 295 105 0.644
OClO- Chlorine dioxide anion 2 A1 418 313 -105 1.334
Li2O dilithium oxide 3 Πu 112 49 -63 2.286
CaS Calcium sulfide 1 Σ 462 365 -97 1.267
OPCl Phosphorus oxychloride 2 A' 308 480 172 0.641
OPCl Phosphorus oxychloride 3 A' 492 290 -202 1.696
H2OH2O water dimer 11 A" 108 157 49 0.688
Mg2 Magnesium diatomic 1 Σg 51 279 228 0.183
ZnCN Zinc monocyanide 3 Π 212 56 -156 3.780