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 MP2/6-31G(2df,p)
Calculated values were scaled by 0.9445.

Species Name mode Symmetry Experiment Theory difference ratio
CH3SeH Methane selenol 12 A" 145 220 75 0.658
C3H4O2 β–Propiolactone 21 A" 113 163 50 0.692
CH3OH Methyl alcohol 12 A" 200 317 117 0.631
C2H4+ Ethylene cation 4 Au 84 -91 -175 -0.929
C2H2 Acetylene 4 Πg 612 476 -136 1.285
HCN+ hydrogen cyanide cation 1 Σ 3050 3591 541 0.849
HCN+ hydrogen cyanide cation 2 Σ 1800 2729 929 0.660
CHONH2 formamide 12 A" 289 -28 -316 -10.418
C3F8 perfluoropropane 13 A2 276 212 -64 1.300
CH3COCH2CH3 2-Butanone 33 A" 87 38 -49 2.265
CH3COOCH3 methyl acetate 27 A" 110 62 -48 1.781
C3H6O 2-Propen-1-ol 24 A 188 108 -80 1.740
C4H8S Thiophene, tetrahydro- 5 A 1464 2955 1491 0.495
C4H8S Thiophene, tetrahydro- 6 A 1441 2955 1514 0.488
C4H8S Thiophene, tetrahydro- 7 A 1321 2939 1618 0.449
C4H8S Thiophene, tetrahydro- 8 A 1276 2939 1663 0.434
C4H8S Thiophene, tetrahydro- 12 A 888 1418 530 0.626
C4H8S Thiophene, tetrahydro- 13 A 829 1297 468 0.639
C4H8S Thiophene, tetrahydro- 14 A 822 1272 450 0.646
C4H8S Thiophene, tetrahydro- 15 A 678 1248 570 0.543
C4H8S Thiophene, tetrahydro- 16 A 472 1229 757 0.384
C4H8S Thiophene, tetrahydro- 17 A 290 1188 898 0.244
C5H8 Cyclopentene 18 A' 254 175 -79 1.454
CH2NN diazomethane 6 B1 406 110 -296 3.683
NH2CN cyanamide 5 A' 408 643 235 0.634
C4H6O2 2,3-Butanedione 21 Bg 240 118 -122 2.027
C2H3NO3 Oxamic acid 3 A' 2600 3453 853 0.753
C2H3NO3 Oxamic acid 15 A' 328 257 -71 1.278
C2H3NO3 Oxamic acid 21 A" 162 66 -96 2.438
C3H6O Oxetane 18 B1 90 -76 -166 -1.186
HCNO fulminic acid 5 Π 224 -362 -586 -0.618
C5H8 1,4-Pentadiene 16 A 137 285 148 0.481
CO+ carbon monoxide cation 1 Σ 2214 2703 489 0.819
C6H6 Benzvalene 10 A1 996 735 -261 1.355
C2F2 difluoroacetylene 4 Πg 270 204 -66 1.323
H2CS- thioformaldehyde anion 4 B1 450 -179 -629 -2.513
NaOH sodium hydroxide 3 Π 300 213 -87 1.408
SiF2+ Silicon difluoride cation 2 A1 350 274 -76 1.277
C5H8 1,3-Pentadiene, (Z)- 22 A' 144 211 67 0.681
C5H8 1,3-Pentadiene, (Z)- 31 A" 456 338 -118 1.349
C5H8 1,3-Pentadiene, (Z)- 32 A" 171 124 -47 1.379
CN Cyano radical 1 Σ 2069 2729 660 0.758
C2H Ethynyl radical 2 Σ 1841 2386 545 0.771
C2H Ethynyl radical 3 Π 372 821 449 0.453
C2H+ Ethynyl cation 3 Π 550 804 254 0.684
CH3OO methylperoxy radical 12 A" 170 127 -43 1.342
CH3 Methyl radical 2 A2" 606 384 -222 1.579
CH2OH Hydroxymethyl radical 8 A 482 693 211 0.695
CH2OH Hydroxymethyl radical 9 A 234 431 197 0.543
C6H8 (Z)-hexa-1,3,5-triene 11 A1 1136 853 -283 1.332
C6H8 (Z)-hexa-1,3,5-triene 19 A2 264 140 -124 1.886
C6H8 (Z)-hexa-1,3,5-triene 24 B1 358 96 -262 3.729
HCCN cyanomethylene 5 Π 129 -458 -587 -0.282
CHCl2 dichloromethyl radical 4 A' 190 294 104 0.646
CH2CHO Vinyloxy radical 10 A" 703 1028 325 0.684
C4H6 Methylenecyclopropane 17 B1 360 279 -81 1.290
O2+ diatomic oxygen cation 1 Σg 1906 1416 -490 1.346
GaF3 Gallium trifluoride 4 E' 192 133 -59 1.447
CaF2 Calcium difluoride 2 A1 120 87 -33 1.377
O3 Ozone 3 B2 1042 2090 1048 0.499
NO Nitric oxide 1 Σ 1904 3259 1355 0.584
NO2 Nitrogen dioxide 3 B2 1618 3456 1838 0.468
N2O4 Dinitrogen tetroxide 9 B2u 265 191 -74 1.387
N2O3 Dinitrogen trioxide 9 A" 63 169 106 0.374
C3O Tricarbon monoxide 5 Π 109 156 47 0.697
VO Vanadium monoxide 1 Σ 1011 2057 1045 0.492
C3 carbon trimer 3 Πu 63 211 148 0.301
SiP Silicon monophosphide 1 Σ 616 907 291 0.679
Cu2 Copper dimer 1 Σg 265 401 137 0.659
ZnH2 Zinc hydride 3 Πu 633 386 -246 1.639
AlO Aluminum monoxide 1 Σ 979 708 -272 1.384
ClOO chloroperoxy radical 2 A' 414 1069 656 0.387
ClOO chloroperoxy radical 3 A' 201 479 278 0.420
OPCl Phosphorus oxychloride 2 A' 308 484 176 0.637
OPCl Phosphorus oxychloride 3 A' 492 287 -205 1.714
H2OH2O water dimer 12 A" 88 38 -50 2.293
H2POH Phosphinous acid 9 A" 375 264 -112 1.424
Mg2 Magnesium diatomic 1 Σg 51 322 271 0.159
Al2 Aluminum diatomic 1 Σg 286 456 171 0.626
ZnCH3 Zinc monomethyl 6 E 315 581 266 0.542
ClONO chlorine nitrite 4 A' 406 311 -95 1.305
ZnCN Zinc monocyanide 3 Π 212 115 -97 1.841
ONONO Nitrosyl nitrite 9 B2 380 285 -95 1.336