return to home page Computational Chemistry Comparison and Benchmark DataBase Release 19 (April 2018) Standard Reference Database 101 National Institute of Standards and Technology
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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 MP2=FULL/cc-pVTZ
Calculated values were scaled by 0.9494.

Species Name mode Symmetry Experiment Theory difference ratio
C3H4O2 β–Propiolactone 21 A" 113 171 58 0.661
CH3CONH2 Acetamide 20 A 259 117 -142 2.208
CH3OH Methyl alcohol 12 A" 200 297 97 0.673
CH3COCH3 Acetone 12 A2 77 38 -39 2.015
C2Cl6 hexachloroethane 4 A1u 61 88 27 0.696
CH3CCl3 Ethane, 1,1,1-trichloro- 6 A2 214 311 97 0.687
C2H4+ Ethylene cation 4 Au 84 -169 -253 -0.498
HCN+ hydrogen cyanide cation 1 Σ 3050 3515 466 0.868
HCN+ hydrogen cyanide cation 2 Σ 1800 2703 903 0.666
CHONH2 formamide 12 A" 289 159 -129 1.812
CH3COCH2CH3 2-Butanone 33 A" 87 16 -71 5.444
CH3COOCH3 methyl acetate 27 A" 110 66 -44 1.672
C3H6O 2-Propen-1-ol 24 A 188 107 -81 1.757
C4H9N Pyrrolidine 36 A" 65 49 -16 1.333
C5H8 Cyclopentene 18 A' 254 180 -74 1.414
CH2NN diazomethane 6 B1 406 234 -172 1.739
NH2CN cyanamide 5 A' 408 610 202 0.669
C4H6O2 2,3-Butanedione 21 Bg 240 133 -107 1.805
C2H3NO3 Oxamic acid 3 A' 2600 3458 858 0.752
C2H3NO3 Oxamic acid 21 A" 162 67 -95 2.420
C3H6O Oxetane 18 B1 90 -70 -160 -1.277
HCNO fulminic acid 5 Π 224 -337 -561 -0.665
C5H8 1,4-Pentadiene 16 A 137 292 155 0.469
CO+ carbon monoxide cation 1 Σ 2214 2731 517 0.811
C6H6 Benzvalene 10 A1 996 738 -258 1.349
H2CS- thioformaldehyde anion 4 B1 450 258 -192 1.744
C5H8 1,3-Pentadiene, (Z)- 22 A' 144 213 69 0.677
C5H8 1,3-Pentadiene, (Z)- 31 A" 456 347 -109 1.313
CN Cyano radical 1 Σ 2069 2761 692 0.749
C2H Ethynyl radical 2 Σ 1841 2406 566 0.765
C2H Ethynyl radical 3 Π 372 779 408 0.477
CH3OO methylperoxy radical 12 A" 170 122 -48 1.392
CH3 Methyl radical 2 A2" 606 476 -131 1.274
CH2OH Hydroxymethyl radical 9 A 234 414 180 0.566
HCCN cyanomethylene 5 Π 129 -465 -594 -0.277
CHCl2 dichloromethyl radical 4 A' 190 297 107 0.639
C4H6 Methylenecyclopropane 17 B1 360 274 -86 1.313
O2+ diatomic oxygen cation 1 Σg 1906 1447 -459 1.317
O3 Ozone 3 B2 1042 2102 1060 0.496
NO Nitric oxide 1 Σ 1904 3065 1160 0.621
NO2 Nitrogen dioxide 3 B2 1618 11913 10295 0.136
N2O3 Dinitrogen trioxide 9 A" 63 161 98 0.391
C3O Tricarbon monoxide 5 Π 109 167 58 0.653
VO Vanadium monoxide 1 Σ 1011 1992 980 0.508
C3 carbon trimer 3 Πu 63 179 116 0.354
SiP Silicon monophosphide 1 Σ 616 973 357 0.633
SO+ sulfur monoxide cation 1 Σ 1360 3544 2184 0.384
SCN thiocyanato radical 1 Σ 1942 2396 453 0.811
PN+ phosphorus nitride cation 1 Σ 1200 1604 404 0.748
OPCl Phosphorus oxychloride 2 A' 308 488 180 0.631
OPCl Phosphorus oxychloride 3 A' 492 292 -200 1.686
NCO isocyanato radical 1 Σ 1921 2349 428 0.818
H2POH Phosphinous acid 9 A" 375 258 -118 1.457
ClONO chlorine nitrite 4 A' 406 288 -118 1.411
ONONO Nitrosyl nitrite 9 B2 380 223 -157 1.708