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/6-31G*
Calculated values were scaled by 0.9443.

Species Name mode Symmetry Experiment Theory difference ratio
CH3OH Methyl alcohol 12 A" 200 330 130 0.606
C2Cl6 hexachloroethane 12 Eu 114 164 50 0.696
C2H4+ Ethylene cation 4 Au 84 -199 -283 -0.423
C2H2 Acetylene 4 Πg 612 398 -214 1.537
CH3CCH propyne 10 E 328 253 -75 1.295
CHONH2 formamide 12 A" 289 -185 -474 -1.562
CH3COOCH3 methyl acetate 27 A" 110 65 -45 1.694
C10H8 naphthalene 27 B2g 770 428 -342 1.798
C3H6O 2-Propen-1-ol 24 A 188 105 -83 1.794
C4H2 Diacetylene 8 Πu 630 484 -146 1.301
C4H2 Diacetylene 7 Πg 482 333 -149 1.447
C3H6O Oxetane 18 B1 90 -48 -138 -1.853
HCNO fulminic acid 5 Π 224 145 -79 1.547
C5H8 1,4-Pentadiene 16 A 137 286 149 0.479
HCCCl Chloroacetylene 5 Π 326 219 -107 1.490
H2CS- thioformaldehyde anion 4 B1 450 -144 -594 -3.131
C2F2 difluoroacetylene 4 Πg 270 210 -60 1.285
C6H6 Benzvalene 10 A1 996 745 -251 1.337
CaO Calcium monoxide 1 Σ 732 555 -177 1.319
NaOH sodium hydroxide 3 Π 300 134 -166 2.245
C5H8 1,3-Pentadiene, (Z)- 22 A' 144 216 72 0.667
C5H8 1,3-Pentadiene, (Z)- 31 A" 456 333 -123 1.369
C5H8 1,3-Pentadiene, (Z)- 32 A" 171 109 -62 1.566
CH3 Methyl radical 2 A2" 606 410 -196 1.479
CH2OH Hydroxymethyl radical 8 A 482 702 220 0.686
CH2OH Hydroxymethyl radical 9 A 234 420 186 0.557
HCCN cyanomethylene 5 Π 129 -485 -613 -0.266
CHCl2 dichloromethyl radical 4 A' 190 296 106 0.642
C4H6 Methylenecyclopropane 17 B1 360 269 -91 1.338
C2Cl2 dichloroacetylene 4 Πg 333 184 -149 1.807
N2 Nitrogen diatomic 1 Σg 2359 1625 -733 1.451
OClO- Chlorine dioxide anion 2 A1 418 327 -91 1.277
Li2O dilithium oxide 3 Πu 112 71 -40 1.569
N2O3 Dinitrogen trioxide 9 A" 63 134 71 0.470
ZnH2 Zinc hydride 3 Πu 633 473 -160 1.337
ClOO chloroperoxy radical 2 A' 414 909 496 0.455
Cl3- trichloride anion 2 Σu 327 223 -104 1.465
CaS Calcium sulfide 1 Σ 462 356 -106 1.298
OPCl Phosphorus oxychloride 2 A' 308 489 181 0.630
OPCl Phosphorus oxychloride 3 A' 492 298 -194 1.652
H2POH Phosphinous acid 9 A" 375 248 -127 1.511
Mg2 Magnesium diatomic 1 Σg 51 297 246 0.172
ZnCN Zinc monocyanide 3 Π 212 85 -127 2.506
ONONO Nitrosyl nitrite 9 B2 380 545 165 0.697