return to home page Computational Chemistry Comparison and Benchmark DataBase Release 18 (October 2016) 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/CEP-31G*
Calculated values were scaled by 0.9494.

Species Name mode Symmetry Experiment Theory difference ratio
C3H4O2 β–Propiolactone 21 A" 113 164 51 0.689
CH3COOH Acetic acid 18 A" 93 70 -23 1.320
CH3OH Methyl alcohol 12 A" 200 324 124 0.616
CH3COCH3 Acetone 12 A2 77 39 -38 1.996
C2H6O2S Dimethyl sulfone 20 B1 262 199 -63 1.314
CH3CCl3 Ethane, 1,1,1-trichloro- 6 A2 214 307 93 0.697
C2H4 Ethylene 7 B2g 940 730 -210 1.288
C2H4+ Ethylene cation 4 Au 84 208 124 0.405
CHONH2 formamide 12 A" 289 -224 -512 -1.291
CH3NO2 Methane, nitro- 11 A" 1583 3085 1502 0.513
C3F8 perfluoropropane 13 A2 276 214 -62 1.292
CHOCH(CH3)CH3 Propanal, 2-methyl- 33 A" 75 59 -16 1.278
CH3COOCH3 methyl acetate 27 A" 110 50 -60 2.188
CF2CCl2 difluorodichloroethylene 7 B1 1327 491 -836 2.705
CF2CCl2 difluorodichloroethylene 8 B1 989 302 -687 3.278
CF2CCl2 difluorodichloroethylene 11 B2 564 429 -135 1.315
CF2CCl2 difluorodichloroethylene 12 B2 323 170 -153 1.904
C3H6O 2-Propen-1-ol 24 A 188 102 -86 1.846
C3H2N2 Malononitrile 6 A1 167 130 -37 1.288
C5H8 Cyclopentene 18 A' 254 187 -67 1.355
C5H8 Spiropentane 8 A2 919 721 -198 1.275
CFClCFCl cis-1,2-dichloro-1,2-difluoroethylene 8 B1 1209 316 -893 3.821
CFClCFCl cis-1,2-dichloro-1,2-difluoroethylene 12 B2 533 394 -139 1.351
C6F6 hexafluorobenzene 7 B2g 715 540 -175 1.323
C6F6 hexafluorobenzene 8 B2g 243 172 -71 1.414
C6F6 hexafluorobenzene 20 E2u 175 129 -46 1.353
NH2CN cyanamide 5 A' 408 711 303 0.574
C4H6O2 2,3-Butanedione 21 Bg 240 119 -121 2.021
CH2CO Ketene 6 B1 528 317 -211 1.665
C2H3NO3 Oxamic acid 3 A' 2600 3435 835 0.757
C2H3NO3 Oxamic acid 15 A' 328 251 -77 1.307
C2H3NO3 Oxamic acid 16 A" 984 772 -212 1.274
C2H3NO3 Oxamic acid 20 A" 315 194 -121 1.621
C2H3NO3 Oxamic acid 21 A" 162 25 -137 6.363
CH3CCCH3 2-Butyne 16 E" 371 173 -198 2.144
C3H6O Oxetane 18 B1 90 -34 -124 -2.642
C3O2 Carbon suboxide 7 Πu 61 182 121 0.334
HCNO fulminic acid 5 Π 224 -343 -567 -0.653
C5H8 1,4-Pentadiene 16 A 137 283 146 0.484
C5H8 1,4-Pentadiene 17 A 102 78 -24 1.301
CH3SSCH3 Disulfide, dimethyl 13 A 117 92 -25 1.270
CO+ carbon monoxide cation 1 Σ 2214 2766 552 0.801
LiOH lithium hydroxide 3 Π 257 381 124 0.674
SiF2+ Silicon difluoride cation 2 A1 350 276 -74 1.268
C5H8 1,3-Pentadiene, (Z)- 22 A' 144 213 69 0.675
C5H8 1,3-Pentadiene, (Z)- 31 A" 456 329 -127 1.386
C5H8 1,3-Pentadiene, (Z)- 32 A" 171 128 -43 1.332
CN Cyano radical 1 Σ 2069 2634 565 0.785
C2H Ethynyl radical 3 Π 372 789 417 0.471
C2H+ Ethynyl cation 3 Π 550 804 254 0.684
CH3 Methyl radical 2 A2" 606 403 -204 1.506
CH2OH Hydroxymethyl radical 8 A 482 756 274 0.638
CH2OH Hydroxymethyl radical 9 A 234 435 201 0.538
C6H8 (Z)-hexa-1,3,5-triene 11 A1 1136 853 -283 1.331
C6H8 (Z)-hexa-1,3,5-triene 19 A2 264 148 -116 1.785
C6H8 (Z)-hexa-1,3,5-triene 24 B1 358 105 -253 3.409
HCCF Fluoroacetylene 5 Π 367 272 -95 1.349
CH3CO Acetyl radical 4 A' 1420 3051 1631 0.465
CCl3 Trichloromethyl radical 2 A1 251 362 111 0.693
CHCl2 dichloromethyl radical 4 A' 190 292 102 0.651
CH2CHO Vinyloxy radical 12 A" 404 317 -87 1.276
C4H6 Methylenecyclopropane 17 B1 360 270 -90 1.332
O2+ diatomic oxygen cation 1 Σg 1906 1226 -680 1.555
PCl5 Phosphorus pentachloride 2 A1' 370 283 -87 1.308
O3 Ozone 3 B2 1042 2343 1300 0.445
NO Nitric oxide 1 Σ 1904 4209 2305 0.452
NO2 Nitrogen dioxide 3 B2 1618 2036 418 0.795
N2O4 Dinitrogen tetroxide 9 B2u 265 179 -86 1.484
N2O3 Dinitrogen trioxide 9 A" 63 154 91 0.410
FO Oxygen monofluoride 1 Σ 1053 2262 1209 0.466
C3 carbon trimer 3 Πu 63 295 232 0.215
MgOH magnesium hydroxide 3 Π 188 116 -72 1.616
C4 Carbon tetramer 4 Πg 323 555 232 0.582
SF5Cl sulfur chloropentafluoride 5 B1 625 443 -182 1.410
SF5Cl sulfur chloropentafluoride 7 B2 505 305 -200 1.654
SF5Cl sulfur chloropentafluoride 11 E 397 242 -155 1.643
PO Phosphorus monoxide 1 Σ 1233 5350 4117 0.231
AlO Aluminum monoxide 1 Σ 979 634 -345 1.544
C2H4O4 Formic acid dimer 13 Au 1050 74 -976 14.157
SCN thiocyanato radical 1 Σ 1942 2441 498 0.796
ClOO chloroperoxy radical 2 A' 414 1025 611 0.404
ClOO chloroperoxy radical 3 A' 201 462 261 0.436
H2OH2O water dimer 8 A' 103 165 62 0.626
H2OH2O water dimer 11 A" 108 161 53 0.671
H2OH2O water dimer 12 A" 88 139 51 0.635
H2POH Phosphinous acid 9 A" 375 258 -118 1.456
Mg2 Magnesium diatomic 1 Σg 51 26 -25 1.978
ClOF3 Chlorine trifluoride oxide 5 A' 319 249 -70 1.279
ClOF3 Chlorine trifluoride oxide 9 A" 412 323 -89 1.276
CH3BO Borane, methyloxo- 7 E 897 1424 527 0.630
ONONO Nitrosyl nitrite 9 B2 380 293 -87 1.297