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 MP2/6-311G**
Calculated values were scaled by 0.9502.

Species Name mode Symmetry Experiment Theory difference ratio
CH3CONH2 Acetamide 20 A 259 383 124 0.676
CH3COOH Acetic acid 18 A" 93 71 -22 1.307
CH3OH Methyl alcohol 12 A" 200 331 131 0.605
C6H6 Benzene 8 B2g 703 374 -329 1.881
CH3CCl3 Ethane, 1,1,1-trichloro- 6 A2 214 332 118 0.645
C2H4+ Ethylene cation 4 Au 84 -111 -195 -0.760
HCN+ hydrogen cyanide cation 1 Σ 3050 3679 629 0.829
HCN+ hydrogen cyanide cation 2 Σ 1800 2759 959 0.652
CHONH2 formamide 12 A" 289 -249 -538 -1.158
CHOCH(CH3)CH3 Propanal, 2-methyl- 33 A" 75 55 -20 1.368
CH3COOCH3 methyl acetate 27 A" 110 37 -73 2.939
C9H8 Indene 40 A" 690 494 -196 1.398
C9H8 Indene 41 A" 549 366 -182 1.498
C6H5CN phenyl cyanide 19 B1 688 524 -164 1.313
C6H5CN phenyl cyanide 20 B1 542 428 -114 1.265
C6H5CHO benzaldehyde 32 A" 688 409 -279 1.684
C6H4O2 parabenzoquinone 17 B2g 241 143 -98 1.686
C6H4O2 parabenzoquinone 30 B3u 109 81 -27 1.335
C3H6O 2-Propen-1-ol 24 A 188 111 -77 1.693
C6H5Cl chlorobenzene 18 B1 685 419 -265 1.632
C6H5Cl chlorobenzene 19 B1 467 347 -120 1.345
C5H12 Pentane 23 A2 131 91 -40 1.445
C4H8S Thiophene, tetrahydro- 5 A 1464 2948 1484 0.497
C4H8S Thiophene, tetrahydro- 6 A 1441 2948 1507 0.489
C4H8S Thiophene, tetrahydro- 7 A 1321 2931 1610 0.451
C4H8S Thiophene, tetrahydro- 8 A 1276 2931 1655 0.435
C4H8S Thiophene, tetrahydro- 12 A 888 1420 532 0.625
C4H8S Thiophene, tetrahydro- 13 A 829 1313 484 0.632
C4H8S Thiophene, tetrahydro- 14 A 822 1286 464 0.639
C4H8S Thiophene, tetrahydro- 15 A 678 1278 600 0.531
C4H8S Thiophene, tetrahydro- 16 A 472 1251 779 0.377
C4H8S Thiophene, tetrahydro- 17 A 290 1203 913 0.241
CH2C(CH3)CH3 1-Propene, 2-methyl- 15 A2 193 146 -47 1.322
C5H8 Cyclopentene 18 A' 254 181 -73 1.407
C4H4N2 Pyridazine 13 A2 421 332 -89 1.269
C6F6 hexafluorobenzene 7 B2g 719 318 -401 2.263
C6F6 hexafluorobenzene 8 B2g 205 111 -94 1.844
NH2CN cyanamide 5 A' 408 681 273 0.599
C4H6O2 2,3-Butanedione 21 Bg 240 120 -120 2.006
C4H2 Diacetylene 7 Πg 482 205 -277 2.356
C6H5F Fluorobenzene 18 B1 685 499 -186 1.373
CH3CCCH3 2-Butyne 16 E" 371 258 -113 1.436
C3H6O Oxetane 18 B1 90 -44 -133 -2.063
C3O2 Carbon suboxide 7 Πu 61 35 -26 1.731
HCNO fulminic acid 5 Π 224 -322 -546 -0.697
C6H4F2 1,4-difluorobenzene 16 B2g 692 521 -171 1.329
C5H8 1,4-Pentadiene 16 A 137 289 152 0.473
HCCBr bromoacetylene 5 Π 295 225 -70 1.314
HCCCl Chloroacetylene 5 Π 326 217 -109 1.499
C6H8 1,4-Cyclohexadiene 19 B1u 108 64 -44 1.696
C6H8 1,4-Cyclohexadiene 23 B2g 403 307 -96 1.311
CO+ carbon monoxide cation 1 Σ 2214 2738 524 0.809
C6H6 Benzvalene 10 A1 996 729 -267 1.366
H2CS- thioformaldehyde anion 4 B1 450 -84 -534 -5.354
CaO Calcium monoxide 1 Σ 732 506 -226 1.446
NaOH sodium hydroxide 3 Π 300 210 -90 1.426
C5H8 1,3-Pentadiene, (Z)- 22 A' 144 212 68 0.679
C5H8 1,3-Pentadiene, (Z)- 31 A" 456 321 -135 1.422
C5H8 1,3-Pentadiene, (Z)- 32 A" 171 111 -60 1.534
CN Cyano radical 1 Σ 2069 2715 646 0.762
C2H Ethynyl radical 2 Σ 1841 2348 507 0.784
C2H Ethynyl radical 3 Π 372 796 424 0.467
CH3 Methyl radical 2 A2" 606 397 -209 1.528
CH2OH Hydroxymethyl radical 8 A 482 698 216 0.690
CH2OH Hydroxymethyl radical 9 A 234 443 209 0.528
C6H8 (Z)-hexa-1,3,5-triene 11 A1 1136 855 -281 1.329
C6H8 (Z)-hexa-1,3,5-triene 19 A2 264 117 -147 2.248
C6H8 (Z)-hexa-1,3,5-triene 24 B1 358 88 -270 4.067
HCCN cyanomethylene 5 Π 129 -477 -606 -0.270
CHCl2 dichloromethyl radical 4 A' 190 306 116 0.620
CH2CHO Vinyloxy radical 10 A" 703 1019 316 0.690
C4H6 Methylenecyclopropane 17 B1 360 259 -101 1.392
O2+ diatomic oxygen cation 1 Σg 1906 1407 -499 1.354
FOOF Perfluoroperoxide 3 A 360 233 -127 1.547
FOOF Perfluoroperoxide 4 A 202 127 -75 1.586
CaF2 Calcium difluoride 2 A1 120 60 -60 1.994
ZnCl Zinc monochloride 1 Σ 391 300 -90 1.300
O3 Ozone 3 B2 1042 2168 1126 0.481
NO Nitric oxide 1 Σ 1904 3383 1478 0.563
NO2 Nitrogen dioxide 3 B2 1618 2326 708 0.696
N2O4 Dinitrogen tetroxide 9 B2u 265 196 -69 1.352
N2O3 Dinitrogen trioxide 9 A" 63 164 101 0.384
VO Vanadium monoxide 1 Σ 1011 1823 812 0.555
Li2O dilithium oxide 3 Πu 112 61 -50 1.825
FO Oxygen monofluoride 1 Σ 1053 2331 1278 0.452
C3 carbon trimer 3 Πu 63 163 100 0.388
PS phosphorus sulfide 1 Σ 739 1284 545 0.575
ClNO2 Nitryl chloride 3 A1 364 278 -86 1.309
PO Phosphorus monoxide 1 Σ 1233 3579 2346 0.345
AlO Aluminum monoxide 1 Σ 979 745 -234 1.314
SCN thiocyanato radical 1 Σ 1942 2414 472 0.805
ClOO chloroperoxy radical 2 A' 414 1057 644 0.391
ClOO chloroperoxy radical 3 A' 201 488 287 0.413
OPCl Phosphorus oxychloride 2 A' 308 459 151 0.670
OPCl Phosphorus oxychloride 3 A' 492 288 -204 1.707
H2POH Phosphinous acid 9 A" 375 262 -113 1.432
AsN Arsenic mononitride 1 Σ 1069 818 -251 1.306
Mg2 Magnesium diatomic 1 Σg 51 27 -24 1.901
ClOF3 Chlorine trifluoride oxide 5 A' 319 248 -71 1.288
ZnCH3 Zinc monomethyl 6 E 315 597 282 0.527
ONONO Nitrosyl nitrite 9 B2 380 219 -161 1.733