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-121G*
Calculated values were scaled by 0.9528.

Species Name mode Symmetry Experiment Theory difference ratio
CH3CONH2 Acetamide 20 A 259 390 131 0.663
CH3COOH Acetic acid 18 A" 93 52 -41 1.790
CH3OH Methyl alcohol 12 A" 200 337 137 0.594
CH3CCl3 Ethane, 1,1,1-trichloro- 6 A2 214 323 109 0.663
C2H2 Acetylene 4 Πg 612 335 -277 1.826
CH3CCH propyne 9 E 633 499 -134 1.268
CHONH2 formamide 12 A" 289 -282 -571 -1.023
C3F8 perfluoropropane 13 A2 276 214 -62 1.287
CH3COOCH3 methyl acetate 27 A" 110 17 -93 6.561
CF2CCl2 difluorodichloroethylene 7 B1 1327 489 -838 2.712
CF2CCl2 difluorodichloroethylene 8 B1 989 292 -697 3.389
CF2CCl2 difluorodichloroethylene 11 B2 564 435 -129 1.298
CF2CCl2 difluorodichloroethylene 12 B2 323 173 -150 1.863
C9H8 Indene 36 A" 917 721 -197 1.273
C9H8 Indene 40 A" 690 443 -247 1.557
C9H8 Indene 41 A" 549 313 -236 1.754
C9H8 Indene 42 A" 415 302 -112 1.371
C9H8 Indene 43 A" 388 187 -201 2.076
C9H8 Indene 45 A" 189 -689 -877 -0.274
C6H4O2 parabenzoquinone 16 B2g 794 496 -298 1.602
C6H4O2 parabenzoquinone 17 B2g 241 -302 -543 -0.799
C6H4O2 parabenzoquinone 30 B3u 109 75 -34 1.454
C3H6O 2-Propen-1-ol 24 A 188 105 -83 1.794
C5H12 Pentane 23 A2 131 92 -39 1.430
C3H2N2 Malononitrile 6 A1 167 130 -37 1.283
C4H5N Pyrrole 10 A2 864 674 -190 1.281
C4H5N Pyrrole 12 A2 614 407 -207 1.507
C4H4O Furan 11 A2 603 385 -218 1.566
C4H4S Thiophene 11 A2 567 418 -149 1.358
CH2C(CH3)CH3 1-Propene, 2-methyl- 15 A2 193 140 -53 1.379
C2Cl4 Tetrachloroethylene 7 B2g 512 344 -168 1.490
C5H8 Cyclopentene 18 A' 254 175 -79 1.451
C4H4N2 Pyridazine 12 A2 751 433 -318 1.735
C4H4N2 Pyridazine 13 A2 421 217 -204 1.937
CFClCFCl cis-1,2-dichloro-1,2-difluoroethylene 8 B1 1209 311 -898 3.888
CFClCFCl cis-1,2-dichloro-1,2-difluoroethylene 12 B2 533 392 -141 1.359
C6F6 hexafluorobenzene 7 B2g 715 249 -466 2.874
C6F6 hexafluorobenzene 8 B2g 243 -138 -381 -1.763
C6F6 hexafluorobenzene 20 E2u 175 126 -49 1.391
NH2CN cyanamide 5 A' 408 731 323 0.558
C4H6O2 2,3-Butanedione 21 Bg 240 108 -132 2.218
C4H2 Diacetylene 6 Πg 627 1132 505 0.554
CH2CO Ketene 6 B1 528 396 -132 1.332
C6H6 Fulvene 15 A2 494 370 -124 1.335
C3H6O Oxetane 18 B1 90 -88 -178 -1.017
C3O2 Carbon suboxide 7 Πu 61 169 108 0.360
HCNO fulminic acid 5 Π 224 -386 -610 -0.581
C6H4F2 1,4-difluorobenzene 16 B2g 692 385 -307 1.796
C6H4F2 1,4-difluorobenzene 18 B2g 374 -292 -666 -1.282
C5H8 1,4-Pentadiene 16 A 137 289 152 0.474
HCCCl Chloroacetylene 4 Π 604 474 -130 1.273
HCCCl Chloroacetylene 5 Π 326 144 -182 2.267
C5H6S Thiophene, 3-methyl- 27 A" 594 429 -165 1.386
CH3SSCH3 Disulfide, dimethyl 13 A 117 86 -31 1.363
CO+ carbon monoxide cation 1 Σ 2214 2714 500 0.816
C2F2 difluoroacetylene 4 Πg 270 104 -166 2.603
LiOH lithium hydroxide 3 Π 257 385 129 0.665
SiF2+ Silicon difluoride cation 2 A1 350 275 -75 1.271
C5H8 1,3-Pentadiene, (Z)- 22 A' 144 213 69 0.677
C5H8 1,3-Pentadiene, (Z)- 31 A" 456 305 -151 1.496
C5H8 1,3-Pentadiene, (Z)- 32 A" 171 103 -68 1.665
CN Cyano radical 1 Σ 2069 2661 592 0.777
C6H5O phenoxy radical 19 B1 472 175 -297 2.692
C2H Ethynyl radical 2 Σ 1841 2307 466 0.798
C2H Ethynyl radical 3 Π 372 785 413 0.474
C2H+ Ethynyl cation 3 Π 550 802 253 0.685
CH3OO methylperoxy radical 12 A" 170 126 -44 1.354
CH3 Methyl radical 2 A2" 606 404 -202 1.500
C6H5 phenyl 17 B1 655 452 -203 1.448
C6H5 phenyl 18 B1 415 150 -265 2.768
CH2OH Hydroxymethyl radical 8 A 482 758 276 0.636
CH2OH Hydroxymethyl radical 9 A 234 448 214 0.522
C6H8 (Z)-hexa-1,3,5-triene 11 A1 1136 854 -282 1.330
C6H8 (Z)-hexa-1,3,5-triene 18 A2 331 248 -83 1.334
C6H8 (Z)-hexa-1,3,5-triene 19 A2 264 103 -161 2.570
C6H8 (Z)-hexa-1,3,5-triene 24 B1 358 88 -270 4.068
CH3CO Acetyl radical 4 A' 1420 3041 1621 0.467
CCl3 Trichloromethyl radical 2 A1 251 366 115 0.685
C6H6 Trimethylenecycopropane 9 A2" 885 693 -192 1.277
CHCl2 dichloromethyl radical 4 A' 190 293 103 0.649
C4H6 Methylenecyclopropane 17 B1 360 253 -107 1.423
ClFO3 Perchloryl fluoride 6 E 405 314 -91 1.288
O2+ diatomic oxygen cation 1 Σg 1906 1217 -689 1.566
MgF2 Magnesium fluoride 3 Πu 165 116 -49 1.419
PCl5 Phosphorus pentachloride 2 A1' 370 285 -85 1.300
O3 Ozone 3 B2 1042 2339 1297 0.445
NO Nitric oxide 1 Σ 1904 3905 2001 0.488
NO2 Nitrogen dioxide 3 B2 1618 2040 422 0.793
N2O4 Dinitrogen tetroxide 9 B2u 265 177 -88 1.501
N2O3 Dinitrogen trioxide 9 A" 63 150 87 0.421
Li2O dilithium oxide 3 Πu 112 83 -29 1.345
FO Oxygen monofluoride 1 Σ 1053 2267 1214 0.464
C3 carbon trimer 3 Πu 63 308 244 0.206
C5H5- cylopentadienyl anion 8 E1" 625 416 -209 1.503
C5H5- cylopentadienyl anion 14 E2" 600 104 -496 5.751
MgOH magnesium hydroxide 3 Π 188 65 -123 2.907
C4 Carbon tetramer 4 Πg 323 523 200 0.617
PS phosphorus sulfide 1 Σ 739 1143 404 0.647
SF5Cl sulfur chloropentafluoride 5 B1 625 437 -188 1.429
SF5Cl sulfur chloropentafluoride 7 B2 505 301 -204 1.680
SF5Cl sulfur chloropentafluoride 11 E 397 236 -161 1.681
PO Phosphorus monoxide 1 Σ 1233 5217 3984 0.236
AlO Aluminum monoxide 1 Σ 979 589 -390 1.662
C2H4O4 Formic acid dimer 13 Au 1050 68 -982 15.451
SCN thiocyanato radical 1 Σ 1942 2459 517 0.790
ClOO chloroperoxy radical 2 A' 414 1024 610 0.404
ClOO chloroperoxy radical 3 A' 201 466 265 0.432
H2POH Phosphinous acid 9 A" 375 251 -124 1.496
Mg2 Magnesium diatomic 1 Σg 51 31 -20 1.666
ClOF3 Chlorine trifluoride oxide 5 A' 319 247 -72 1.294
ClOF3 Chlorine trifluoride oxide 6 A' 224 175 -49 1.277
ClOF3 Chlorine trifluoride oxide 9 A" 412 315 -97 1.310
ClONO chlorine nitrite 4 A' 406 319 -87 1.273
CH3BO Borane, methyloxo- 7 E 897 1436 540 0.624
ONONO Nitrosyl nitrite 9 B2 380 240 -140 1.585